John Hayes, Managing Partner

Constantine Law was founded by John Hayes, one of London's leading employment lawyers. John advises UK corporates in the financial services, employment agencies, retail and construction sectors.

He is also one of London's leading solicitors in restrictive covenant disputes and an experienced High Court practitioner. He has obtained numerous injunctions for a range of leading corporate clients, in the High Court, in recent years. John has a very solutions orientated and commercial approach.

John Qualified as a solicitor in 2001 and as a barrister in 1993. He is an experienced advocate and has years of experience in litigating in the Employment Tribunal, and the Employment Appeal Tribunal in unfair dismissal, whistleblowing and equal opportunities cases. 

John's client base is entrepreneurial and this prompted him to set up Constantine Law. He is recognised in the Legal 500 and has previously headed the London employment team of a large national law firm.

John has particular expertise in business protection and works closely with some of the leading barristers in the field to protect his client's commercial interests. He has great experience in the arena of a-typical working, including consultancy agreements, IR35, CIS and the tax implications of each. He works closely with leading accountants to provide joined-up solutions for his clients.

John is a member of the Employment Lawyers Association and the leading Irish entrepreneurial organisation, the Irish International Business Network (IIBN). He is also an active member of the Institute of Directors (IOD). John is a contributor to the Huffington Post and appears regularly on news media including the LBC and Television. He is also a regular contributor to leading trade magazines on employment matters.

John is married to Ceri, with three children, Joseph, Theo and Aoife. He is a member of the Hampstead Triathlon Club and raises money through Olympic distance triathlons. His other main passions are public affairs (standing in the 1997 General Election) and London's cultural scene.

Simon Fenton , Partner

Simon joined Constantine Law in May 2018 from the employment team of a large national law firm. Simon qualified as a solicitor in 1993.

He specialises in company reorganisations, large scale redundancies, boardroom disputes, HR advice, employment law training, High Court injunctions, Employment Tribunal litigation(unfair dismissal and discrimination) and High Court injunctions. Simon has particular expertise in the tech, recruitment and hospitality sectors.

Simon’s first degree was in Management Science and he initially worked in pharmaceutical marketing at Boots and in the hospitality industry in Australia. Simon then spent 2 years in Hong Kong teaching at the British Council. He then decided to retrain as a lawyer and took another degree, this time in Law, before training at the City firm of Wilde Sapte (now SNR Denton).  In his circuitous route to becoming a solicitor Simon picked up many useful skills particularly understanding the perspective of business and working in partnership with clients (rather than just advising and then backing off!)

In Chambers Legal Directory, he is rated as a Band One ranked lawyer, where they’ve said he is: “head and shoulders above the rest in terms of practicality of advice and understanding things from a business standpoint.” and “Clients praise his excellent guidance across a range of employment issues.”

The Legal 500 UK guide to outstanding lawyers nationwide names him in the elite ‘Leading Lawyers’ list and they say: “Fenton is praised for unique combination of depth, breadth and awareness.

In his spare time Simon rides his bike (Land’s End to John O’Groats in 2017), and sits on the boards of Swings and Smiles (a charity providing services for children with special needs) and the Newbury Spring Festival (a classical music festival).  However, what seems to take up most of his time is gaining weight, losing weight and parking!

Alan Lewis, Partner


T: 07814 384 745


With more than twenty years’ experience as an employment lawyer and an additional decade in the corporate law arena before that, Alan is renowned among clients for his dedicated approach and attention to detail. He mainly advises employers and his clients range from small SMEs to larger companies with thousands of employees. Whether a client's concern is a complex TUPE service provsion change, a senior leaver trying to poach customers in breach of restrictive covenants or a potentially damaging employment tribunal claim, Alan has helped to steer tens of companies to a successful outcome.

Initially having practised as a corporate lawyer, Alan has a keen interest in the commercial issues surrounding a corporate client's given situation and he draws on that interest to focus on solutions to minimise disruption to the client's business and its reputation.

Alan advises employers on how best to streamline their management of staff and resources so that managers reduce the amount of time spent on areas where they add little value to the business.

He also assists directors and other senior executives in negotiating contracts with their employing company, or in forging a favourable exit deal if they are looking to move elsewhere.

One of his clients in the legal profession, a leading road traffic lawyer, says:

"Alan is one of the most caring and intelligent Solicitors I have ever had the pleasure to meet. As a fellow solicitor I am proud to say that I look up to Alan as a shining example of best practice within the profession."

Clients facing particularly challenging and stressful situations are delighted with Alan's style. A senior director says:

"His caring yet forensically detailed approach put me at ease, and ensured that I achieved the best possible result."

The HR Director of a retail company with more than 800 UK branches says:

"He comes up with unique, creative solutions that you cannot find in a text book or from your average solicitor off the street. He is able to do this because of his ability to truly understand the needs of his clients and due to the outstanding level of care that he delivers."

Alan is married to Donna and they have three grown up children. Alan and Donna have been keen brass musicians, playing key roles with some of the UK's premier bands. Alan is a keen networker and published a book on networking back in 2012.

Sarah Wallace, Partner


I am a leading corporate crime, professional discipline and financial services investigations lawyer with over 20 years’ experience. I represent clients under or at risk of criminal or regulatory investigation or prosecution: ‘the go to choice for a tough and no nonsense litigator who will leave no stone unturned in defence of clients’ Legal 500, 2019. I give expert legal, personal and practical advice to senior executives and corporates and specialise in FCA, SFO, CMA, CPS, ICO, HMRC, DOJ, SEC, police and professional discipline investigations eg SRA, IFoA, FRC.

I represent senior executives and firms through the stressful, uneasy and challenging time when faced with a criminal, regulatory or internal investigation that can impact on careers, reputation, health, wealth and business performance. My aim is to protect reputations and extricate a client from their involvement with an investigation as quickly as possible.

My client can be a suspect, under or at risk of investigation, whistleblower, witness or victim and my cases often have a cross-border element. My practice includes advice on internal investigations, responding to information requests, interview advice, self-reporting, compliance monitoring, training and M&A due diligence.

I have extensive experience defending complex FCA civil, criminal and regulatory cases for senior executives and firms. High profile FCA cases include LIBOR, Newton Investment Management, Keydata and insider dealing cases eg Neutec Pharma, Operation Tabernula, Operation Saturn, Oce/Mizuho. I help firms with systems and controls improvement, compliance monitoring, mis-selling, remediation and customer contact exercises.

The high profile SFO investigations I have been involved in recently include LIBOR (Barclays, Lloyds), BAT, Rolls-Royce, Autonomy, Quindell, Unaoil and overseas bribery. My clients are from the financial services, pharmaceutical, energy, engineering, professional services and aerospace sectors.

I am sought out and quoted in the FT, Guardian, Daily Telegraph, Evening Standard, New York Times, Bloomberg, Reuters, PA and am an expert commentator for BBC News. I speak regulatory at industry events.

I am interested in work culture and I write about diversity, inclusion and well-being in workplaces in national press and social media. I am a 'CityInfluencer' to encourage cultural change in the City, and speak at events and hold roundtables for employers to share best practice.

➞ Professional Discipline, Chambers 2019: “She’s very engaged, very committed to the cases, creative and tries to find the right solution for clients”.

➞ Financial Crime, Chambers 2019: Noted for her technical expertise in fraud and insider dealing investigations. “Highly committed to the defence of individuals”…”she really understands what clients are going through”.

➞ Financial Services, Legal 500 2019: ‘bright and hard-working” “wise beyond her years and brings heaps of experience to any dispute”.

➞Fraud/White Collar Crime, Legal 500 2019: “well-regarded expert in white-collar crime”

Prior to joining Constantine Law, Sarah was a partner and led the Regulatory & Criminal Investigations Group in a large national law firm.

Caroline Glacken, Senior Associate

Caroline Glacken qualified in 2012 and joined Constantine Law in January 2016 having previously worked in the London office of a large national law firm.

Caroline is an experienced employment lawyer and a member of the Employment Lawyers Association. Caroline is adept at providing legal support to HR teams, including support through complex internal investigations and processes and preparing contractual documentation and handbooks. Caroline has significant experience in Employment Tribunal litigation including unfair dismissal and complex discrimination proceedings as well as High Court Litigation in relation to injunctive relief and business protection.

Caroline is also experienced in providing integrated business immigration solutions to corporate clients who want to sponsor their workers or require business visitor visas. Caroline is a member of the Immigration Law Practitioner's Association and works closely with immigration barristers to achieve great results for clients.

Caroline is an active member of Irish business networks in London; the Irish International Business Network (IIBN) and The London Irish Construction Network (TLICN). Caroline also works closely with the London Irish Centre.

Matthew Brain, Senior Associate

Matthew qualified as a solicitor in September 1991, specialising in employment law from an early stage. He became a partner at a leading national firm of solicitors in 2003 where he ultimately headed the Northern employment law team. 

In January 2012, Matthew embraced his inner-entrepreneurial spirit and left the (relative) comfort of private legal practice and established his own successful HR and Employment Law consultancy business, where his clients have continued to benefit from what one client recently called his “rare blend of legal expertise and pragmatism”. 

Matthew joins Constantine Law with over 25 years` experience of advising clients of all sizes in both the private and public sector on all aspects of employment law.  He has over 25 years’ experience in conducting Employment Tribunal cases for employers and employees, with a principal interest in discrimination claims. Matthew has specialist experience as an Employment Tribunal advocate.  Matthew also has highly regarded experience in the field of the TUPE 2006 Regulations and business acquisitions and outsourcing, as well as in presenting seminars to clients and providing bespoke in-house training for senior employees and in-house HR teams.  Matthew lives in Yorkshire with his wife Sarah, and two young boys Samuel and Oliver. A former National League rugby player, Matthew now participates in a range of less painful sports such as badminton and squash, and is a keen classical and electric guitarist.

Interested in Joining the Team?

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