Siân McGibbon

Public and Administrative

Siân regularly appears in the Administrative Court as both sole and led counsel. She acts across a full spectrum of public law cases, from homelessness and social care, to education and healthcare, to commercial procurement cases. She has a particular specialism in cases raising issues under Human Rights Act 1998 and Equality Act 2010.

Siân is recognised for her ability to ‘use public law principles to craft a winning strategy in difficult cases’, and has been involved in a number of landmark decisions raising novel public law issues:

• R (Campbell) v. Ealing London Borough Council [2023] EWHC 10 (Admin) – Siân acted as sole counsel for the claimant in this judicial review of the defendant’s breach of duty under Care Act 2014. Siân acted in the successful application to the Court of Appeal and remains instructed in the forthcoming appeal, led by Galina Ward KC.
• R (Cort) v. London Borough of Lambeth [2022] EWHC 1085 (Admin) – Siân acted for the successful claimant in this successful application for judicial review of the defendant’s refusal to provide the claimant with accommodation under the national ‘Everyone In’ initiative during the Covid-19 pandemic on the basis of failure to take into account relevant considerations. She also acted as junior counsel, led by Jamie Burton KC, in the closely related challenge to failure by the Secretary of State for Housing, Communities, and Local Government to publicise its decision to end the ‘Everyone In’ policy ([2022] EWHC 85 (Admin) and [2022] EWCA Civ 1059).
• Association of Chartered Certified Accountants v. Awodola [2021] EWCA Civ 1635 – Siân appeared unled respondent, opposite a leading silk, and secured a pro bono costs order of £25,000.00 for the Access to Justice Foundation. She had also acted in the successful application for judicial review before Foster J ([2020] EWHC 3059 and [2020] EWHC 3369).

She has a strong record in dealing with urgent, complex, and sensitive cases, and has been praised in judgments for her ‘helpful and constructive’ approach. Recent illustrations include:

• R (Webb) v. Bromley [2023] EWHC 2091 (Admin) – Siân acted for the local authority in this expedited judicial review of a decision to grant planning permission for the construction of a new cancer treatment unit at the Princess Royal University Hospital, challenged on the grounds of apparent bias.
• R (ZOS) v. Secretary of State for the Home Department [2022] EWHC 3567 (Admin) – Siân was instructed for the claimant in this successful application for judicial review of the defendant’s breach of statutory duties. She represented the claimant in successfully resisting the defendant’s application for relief from sanction following breach of the mandatory order secured in the underlying proceedings.
• R (BL) v. Islington [2021] EWHC 3044 (Admin) – Siân was instructed as sole counsel for the local authority in this judicial review which involved numerous ancillary issues regarding the claimant’s litigation capacity.

Urgent Applications and Interim Relief

Siân has been recognised for her ability to act in applications for interim relief in the administrative court, including in out of hours applications. Recent cases include:

• R (OLO, AMA, and OCO) v. Redbridge (CO/488/2022) – Siân acted for the claimants in this claim for breach of section 17 Children Act 1989, which secured an increase of almost 100% in support provided to the family.
• R (NA) v. Hammersmith & Fulham (CO/2202/2021) – Siân acted in this application for urgent interim relief on the basis that there was ‘reason to believe’ the applicant may be in priority need pursuant to the (then newly implemented) s.78 Domestic Abuse Act 2021. The client secured interim accommodation and an order that the authority pay her costs.
• R (PG) v. Hammersmith & Fulham (CO/4204/2021, HHJ Lickley QC, 17 December 2021), in which she was successful in obtaining interim relief both on the papers and at an oral hearing, in the context of the spread of the OMICRON variant of Covid-19 on the grounds that the local authority had failed to take into account a material relevant consideration.

Human Rights and Civil Liberties

As a pupil Siân worked on a number of the leading cases on the application of the public sector equality duty under s. 149 Equality Act 2010 (Forward v Aldwyck Housing Group Ltd [2019] EWHC 24 (QB), London and Quadrant v Patrick [2019] EWHC Civ 1263 (QB), and Powell v Dacorum [2019] EWCA Civ 29). She was also involved in judicial review challenges under the Equality Act 2010 including the high profile challenge to the ‘Right to Rent’ policy (R (Goloshvili) v Secretary of State for the Home Department [2019] EWHC 1263).

She is presently instructed in a number of human rights matters, including:

• Sharaky v Clearspring Ready Homes [2022] EWHC 2019 (QB) – Siân acted for the claimant (initially as sole counsel in the successful application for interim relief, later as led counsel in the recent three-day High Court trial). Siân continues to act in the ongoing related application to the European Court of Human Rights.
• Sheta v Redbridge (HHJ Parfitt, 31 March 2022) – Siân represented the appellant in successfully challenging the local authority’s failure to comply with s. 149 Equality Act 2010.
• R (Campbell) v Ealing (CO/1931/2022) – Siân acted for the claimant in the successful applications for permission and interim relief, and is instructed in the substantive proceedings listed for December 2022.
  The case raises a serious allegation of victimisation contrary to section 27 Equality Act 2010.

She also has a growing Caribbean practice in this area:

• Betaudier v Attorney General of Trinidad and Tobago [2021] UKPC 7 – Siân was instructed as junior counsel for the successful appellant in a claim against the state for wrongful arrest and unlawful detention.
• Duncan & Jokhan v Attorney General of Trinidad and Tobago [2021] UKPC 17 – Siân was instructed as junior counsel for the successful appellant in a claim for damages for breach of the constitutional right to liberty and security of the person.
• Ministry of Social Development and Family Services v P (JCPC 2021/0021) – Siân is instructed as junior counsel for the appellant in this upcoming constitutional appeal concerning the lawfulness of a policy in Trinidad and Tobago which restricts disability benefits to those with a ‘permanent’ condition.

Local Government including Local Government Finance

Siân regularly acts both for and against local authorities in a range of matters, often in complex matters in which multiple statutory duties (including under Care Act 2014, Children Act 1989, and Housing Act 1996, amongst others) are engaged. She has spent time seconded in house at a major local authority so has insight into the practical pressures and issues which face local government and the solicitors who act for them.

Siân has been involved in a number of significant cases concerning local authority powers and duties:

• Zaman v. Waltham Forest [2023] EWCA Civ 322 – Siân was instructed as sole counsel for the appellant in the first appeal and in the successful application for permission to appeal to the Court of Appeal. She was led by Jamie Burton KC in the successful substantive appeal to the Court of Appeal. The case raised issues of wider importance regarding the adoption of ‘zoning’ policies by local authorities when moving families outside of their local area.
• Rowe v. London Borough of Haringey [2022] EWCA Civ 1370 – Siân acted as sole counsel for the appellant in the first appeal, and in the successful application for permission to appeal to the Court of Appeal. She remained instructed as junior counsel alongside Toby Vanhegan and Justin Bates in the substantive proceedings before the Court of Appeal and application for permission to appeal to the Supreme Court. The case raises issues of wider significance as to the standards of overcrowding to be applied to houses in multiple occupation.
• Stanley v. Welwyn Hatfield [2020] EWCA Civ 1458 – Siân appeared as led counsel for the appellant in this significant case. The Court of Appeal clarified the status of statutory review decisions notified out of time by the local authority, and the proper route for bringing a statutory appeal against such a decision.

Education

Siân has experience across the full spectrum of education law, and regularly acts for parents and students, as well as a number of different local authorities and education providers. She has a particular interest in cases at the intersection of education law and administrative law, and is regularly instructed in claims for judicial review in this area involving the Office of the Independent Adjudicator for Higher Education and the Department for Education.

NHS, Health and Community Care

Siân accepts instructions across all aspects of health and social care law. She has previously acted for the British Medical Association, the Department for Health and Social Care, and regularly represents claimants in challenging decisions made by public bodies in this area. She is a contributor to the forthcoming edition of ‘NHS Law and Practice’ published by the Legal Action Group.

Procurement & Commercial Public Law

Siân has a growing practice in commercial judicial review, and accepts instructions from both public bodies and private parties. Recent work highlights include:

• Advising a small business in relation to procurement issues arising from funding obtained through a local authority from the Department for Levelling-Up, Housing and Communities.
• R (on the application of Good Law Project) v. Secretary of State for the Home Department [2021] EWHC 346 – Siân was instructed as junior counsel for the Secretary of State, led by Philip Moser KC, in this landmark Covid-19 procurement policy judicial review.
• Akinola v. Bexley (HHJ Saggerson, 6 May 2021) – Siân successfully defended a challenge to a Service Level Agreement entered by a local authority brought on the basis that the pricing structure gave rise to ‘apparent bias’.

Siân is a member of the Lexis PSL expert panel on procurement law and her analysis of the latest cases in this area are regularly published in their commercial and public law highlights. Her recent work has included coverage of the high profile Covid-19 procurement challenges.

Statutory Appeals

Siân has extensive experience of acting in statutory appeals across a range of areas. Her recent work includes:

• Hynek v. Islington (HHJ Backhouse, 12 July 2022) – Siân appeared for the successful appellant in this statutory appeal which raised novel arguments as to the rights of EU citizens with pre-settled status who claim to have ‘retained worker status’ following the end of the transition period.
• OH v. Lambeth (Stephen Midwinter KC, 26 November 2021) – Siân acted for the successful appellant in this statutory appeal pursuant to s. 204 Housing Act 1996. The case raised a novel point of law as to the relevant point in time to be considered by a local authority when determining whether an applicant has a resident dependent child for the purposes of assessing priority need.
• RO v. Bexley (HHJ Venn, 9 July 2021) – Siân acted for the successful respondent in a rare application pursuant to CPR 52.18. The appeal was struck out and the authority was awarded its costs of the proceedings.

Caribbean Law

Siân also has extensive experience of appearing before the Privy Council in constitutional and public law cases from Caribbean jurisdictions. Recent work in this area includes:

• Peters v. Permanent Secretary [2023] UKPC 23 – Siân was instructed as junior counsel in this Privy Council appeal against a decision to dismiss an application for judicial review of secondary legislation which restricted access to disability assistance to those with a ‘permanent’ disability.
• Duncan & Jokhan v. Attorney General of Trinidad and Tobago [2021] UKPC 17 – Siân acted for the successful appellants in this constitutional appeal against the Attorney General of Trinidad and Tobago, led by Anand Beharrylal KC.
• Betaudier v. Attorney General of Trinidad and Tobago [2021] UKPC 7 – Siân acted for the successful appellant in this appeal claim for damages for unlawful arrest and detention, led by Anand Beharrylal KC.

Planning

Siân has a varied practice spanning all areas of planning, infrastructure, and environmental law. She has experience of acting for planning authorities, land owners, developers, and individuals from advisory stages through to final hearings and appeals. She has a particular interest and specialism in cases which raise issues at the intersection of planning, public, and environmental law.

Recent reported cases and court highlights include:

• R (Webb) v. Bromley London Borough Council [2023] EWHC 2091 – Siân acted for the local authority in successfully defending this application for judicial review, as sole counsel at the permission stage and subsequently led by Richard Drabble KC and Paul Brown KC at the substantive hearing of this judicial review. The case raises issues of wider importance regarding declaration of interests by voting members of local authority planning committees.
• Thurrock London Borough Council v. Persons Unknown (QB-2019-02738, awaiting final judgment): Siân was instructed as junior counsel for the local authority (led by Tim Straker KC) in this application for injunctive relief pursuant to section 187B Town and Country Planning Act 1990. The case will return for final determination following judgment by the Supreme Court in Wolverhampton City Council v. London Gypsies and Travellers (2022/0046).
• Silochan v. Cedeno (Town and Country Planning Division) [2023] UKPC 5: Siân appeared before the Privy Council as junior counsel for the successful appellants in this significant appeal which raised questions of general importance regarding the proper approach to construction, prosecution, and sentencing of planning offences.

Recent advisory work includes:

• Advising a developer in relation to the sequencing of works and implications of the judgment of the Supreme Court in Hillside Parks Ltd v. Snowdonia National Park Authority [2022] UKSC 30 for proposals involving overlapping planning permissions.
• Advising a local campaign group in relation to grounds for judicial review of a decision by the Environment Agency to grant an environmental permit for a major incineration operation.
• Advising a local authority in relation to an appeal against a decision to issue a certificate of lawful commencement of development at a site in north London which attracted significant local controversy.

Siân is on the Lexis Expert Panel for planning and environmental law. She is a member of both the Planning and Environmental Bar Association (PEBA) and UK Environmental Law Association (UKELA).

Environmental & Planning Law

Siân has a varied practice spanning all areas of planning, infrastructure, and environmental law. She has experience of acting for planning authorities, land owners, developers, and individuals from advisory stages through to final hearings and appeals. She has a particular interest and specialism in cases which raise issues at the intersection of planning, public, and environmental law.

Recent reported cases and court highlights include:

• R (Webb) v. Bromley London Borough Council [2023] EWHC 2091 – Siân acted for the local authority in successfully defending this application for judicial review, as sole counsel at the permission stage and subsequently led by Richard Drabble KC and Paul Brown KC at the substantive hearing of this judicial review. The case raises issues of wider importance regarding declaration of interests by voting members of local authority planning committees.
• Thurrock London Borough Council v. Persons Unknown (QB-2019-02738, awaiting final judgment): Siân was instructed as junior counsel for the local authority (led by Tim Straker KC) in this application for injunctive relief pursuant to section 187B Town and Country Planning Act 1990. The case will return for final determination following judgment by the Supreme Court in Wolverhampton City Council v. London Gypsies and Travellers (2022/0046).
• Silochan v. Cedeno (Town and Country Planning Division) [2023] UKPC 5: Siân appeared before the Privy Council as junior counsel for the successful appellants in this significant appeal which raised questions of general importance regarding the proper approach to construction, prosecution, and sentencing of planning offences.

Recent advisory work includes:

• Advising a developer in relation to the sequencing of works and implications of the judgment of the Supreme Court in Hillside Parks Ltd v. Snowdonia National Park Authority [2022] UKSC 30 for proposals involving overlapping planning permissions.
• Advising a local campaign group in relation to grounds for judicial review of a decision by the Environment Agency to grant an environmental permit for a major incineration operation.
• Advising a local authority in relation to an appeal against a decision to issue a certificate of lawful commencement of development at a site in north London which attracted significant local controversy.

Siân is on the Lexis Expert Panel for planning and environmental law. She is a member of both the Planning and Environmental Bar Association (PEBA) and UK Environmental Law Association (UKELA).

Recent reported cases and court highlights include:

• R (Webb) v. Bromley London Borough Council [2023] EWHC 2091 – Siân acted for the local authority in successfully defending this application for judicial review, as sole counsel at the permission stage and subsequently led by Richard Drabble KC and Paul Brown KC at the substantive hearing of this judicial review. The case raises issues of wider importance regarding declaration of interests by voting members of local authority planning committees.
• Thurrock London Borough Council v. Persons Unknown (QB-2019-02738, awaiting final judgment): Siân was instructed as junior counsel for the local authority (led by Tim Straker KC) in this application for injunctive relief pursuant to section 187B Town and Country Planning Act 1990. The case will return for final determination following judgment by the Supreme Court in Wolverhampton City Council v. London Gypsies and Travellers (2022/0046).
• Silochan v. Cedeno (Town and Country Planning Division) [2023] UKPC 5: Siân appeared before the Privy Council as junior counsel for the successful appellants in this significant appeal which raised questions of general importance regarding the proper approach to construction, prosecution, and sentencing of planning offences.

Recent advisory work includes:

• Advising a developer in relation to the sequencing of works and implications of the judgment of the Supreme Court in Hillside Parks Ltd v. Snowdonia National Park Authority [2022] UKSC 30 for proposals involving overlapping planning permissions.
• Advising a local campaign group in relation to grounds for judicial review of a decision by the Environment Agency to grant an environmental permit for a major incineration operation.
• Advising a local authority in relation to an appeal against a decision to issue a certificate of lawful commencement of development at a site in north London which attracted significant local controversy.

Siân is on the Lexis Expert Panel for planning and environmental law. She is a member of both the Planning and Environmental Bar Association (PEBA) and UK Environmental Law Association (UKELA).

Cross-practice

Landmark's barristers often work at the intersection of our core practice areas; bringing a wide range of skills, knowledge and experience to bear on a particular dispute or issue facing a client.

Our focus is always on achieving the best possible outcome for our client. By viewing the client's objectives in a holistic way - and not purely through the lens of one rigidly-defined legal area - we deliver the best possible advice and representation in complex matters that engage multiple specialist areas of law. 

Whether it's providing support as an individual cross-practice barrister or a cross-disciplinary team of Landmark counsel, we are able to draw on an outstanding array of complementary skillsets and knowledge bases. This often achieves a better result than instructing multiple barristers from different specialist sets. This also improves the quality of client care through increased levels of communication, quicker response times, and a coordinated approach to clerking and fees, made possible by our team-based cross-practice approach.

Please contact our practice management team for more information.

Local Government

Siân regularly acts both for and against local authorities in a range of matters, often in complex matters in which multiple statutory duties (including under Care Act 2014, Children Act 1989, and Housing Act 1996, amongst others) are engaged. She has spent time seconded in house at a major local authority so has insight into the practical pressures and issues which face local government and the solicitors who act for them.

Siân has been involved in a number of significant cases concerning local authority powers and duties:

• Stanley v Welwyn Hatfield [2020] EWCA Civ 1458 – Siân appeared as led counsel for the appellant in this significant case. The Court of Appeal clarified the status of statutory review decisions notified out of time by the local authority, and the proper route for bringing a statutory appeal against such a decision.
• Rowe v London Borough of Haringey [2022] EWCA Civ 1370 – Siân acted as sole counsel for the appellant in the first appeal, and in the successful application for permission to appeal to the Court of Appeal. She remained instructed as junior counsel alongside Toby Vanhegan and Justin Bates in the substantive proceedings before the Court of Appeal and she continues to act in the pending application for permission to appeal to the Supreme Court. The case raises issues of wider significance as to the standards of overcrowding to be applied to houses in multiple occupation.
• Zaman v Waltham Forest (HHJ Gerald, 21 July 2022) – Siân was instructed as sole counsel for the appellant in the first appeal and in the successful application for permission to appeal to the Court of Appeal. The case raises issues of wider importance regarding the adoption of ‘zoning’ policies by local authorities when moving families outside of their local area.