Siân is an Of Counsel within the leading employment and data protection team at Herbert Smith Freehills.
Siân draws on her experience as a practising barrister to provide clients with considerable technical expertise, commercial acumen and a pragmatic approach.
Siân has experience in cases spanning the range of employment and discrimination law, including whistleblowing, redundancy, TUPE, unfair dismissal and wage related claims. Siân has earned praise for her conscientious, professional and insightful approach. Clients are particularly impressed with her sensible approach to litigation, and Siân has been described as having "clout, gravitas and oodles of technical skill" (Legal 500 UK 2025).
Siân has particular experience advising on complex discrimination claims, including disability, pregnancy and maternity, race and sexual harassment issues. Siân has extensive advocacy experience in the Employment Tribunals as well as in County Court and High Court litigation and arbitral proceedings, and she has acted as an independent investigator hearing grievance and disciplinary matters for a variety of organisations.
Siân has a significant highly specialist data protection practice advising on a wide range of privacy related topics within the employment sphere, including GDPR compliance, strategic responses to DSARs, dealing with regulator complaints as well as cross-border issues.
Siân regularly advises and presents on data privacy and discrimination/bias issues arising from the use of AI technology, and regularly advises on data protection and privacy issues arising in respect of investigations and monitoring, responses to data breaches and complex regulatory advice (including on extra-territorial effect).
Experience & expertise
Selected matters
- Tesco on the defence of equal pay claims brought by several thousand store colleagues
- A leading insurance broker, in relation to a claim against David Gordon (the former CEO of Marsh-JLT’s Fine Art, Jewellery and Specie (“FAJS”) team, Ed Broking LLP (a competing insurance broker) and BGC Partners, Inc. (Ed Broking LLP’s parent) arising out of the Defendants’ unlawful recruitment of 20 employees who resigned from Marsh-JLT’s FAJS team in January 2020 in order to join Ed Broking
- Jefferies in relation to claims brought by a former senior research analyst, Milan Radia, who was dismissed by Jefferies because an Employment Tribunal found that he had lied in the evidence he gave to the tribunal under oath. Mr Radia brought two sets of proceedings and his appeals against the original decisions were heard by the EAT
- A financial institution on a claim of historic sexual harassment and attempted sexual assault by a former employee instigated following the #MeToo campaign
- An educational establishment on the setting up and operation of a very high profile, but internal, disciplinary process involving a senior leader, following an allegation of sexual harassment
- A financial services firm on a complex disability discrimination matter with the risk of career losses.
- A number of clients on the implementation of the GDPR in the UK and across Europe
- Various organisations on responding to data subject access requests in the context of actual or threatened litigation
- A recruitment agency on the defence of claims for victimisation related to sexual harassment allegations in the Employment Tribunal*
- Claimant employees in a class action against Betfred in Lawless and ors v Done Brothers t/a Betfred, for unlawfully attempting to unilaterally change the terms and conditions of hundreds of employees in its betting shops following its acquisition of Tote bookmakers*
- The appellant in Nyathi v Secretary of State UKEAT/0465/17/JOJ which considered the scope of the employment tribunal's duty to make reasonable adjustments for litigants in person with disabilities*
Data Protection
- A number of clients on the implementation of the GDPR in the UK and across Europe
- Various organisations on responding to data subject access requests in the context of actual or threatened litigation
- Strategic advice on contentious employment issues, including data protection implications, before litigation for various clients, particularly in the financial services sector.
- Various organisations on the development and implementation of AI technology, both in relation to workforce and more widely
- Various clients in relation to discrete data protection queries under the GDPR and UK GDPR, including in relation to security breaches, regulatory investigations, data processing activities and cross-border data transfers
- A recruitment agency on data subject access request and data implications arising from litigation*
- A law firm on data subject access request and legal privilege exemption*
*Experience gained prior to Herbert Smith Freehills
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