Our Team

The senior members of our team have been trained at and have worked in the leading corporate law firms in London. Our approach is to use our core team members and, when required, to draw on the skills of a range of other consultants with whom we regularly work.

Gideon Nellen BA (UCT) Solicitor specialises in corporate and commercial law and in particular in transactional work. After his articles with Clifford Turner (now Clifford Chance) he worked at Freshfields and at Herbert Smith in their corporate departments. In 1991 Gideon set up NELLEN as a niche corporate law firm specialising in mergers and acquisitions, restructurings, private equity and financing transactions involving SMEs.

Mark Cawthron is a corporate tax consultant to NELLEN. He was for a number of years a tax partner at Pinsent Masons LLP following which he was a partner at Bryan Cave LLP. Mark specialises in general corporate tax, including advice on transactional work and on employee share participations. He is currently also one of the editors of the principal CCH online tax publication, Tax Reporter.

Tessa Mayhew BA (Oxon) Solicitor is consultant to NELLEN. Tessa was a litigation partner at Herbert Smith until 1991 when she left the City and became involved in renewable energy/environmental issues. She was Managing Director and a shareholder of The Cornwall Light & Power Company Limited, which developed and operated Goonhilly Downs Windfarm, one of the earliest UK windfarms, until 2005 when the company was sold (a process which she led). She has also worked in-house for National Wind Power Limited (subsequently RWE Npower Plc).

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Our Team

Gideon Nellen
Mark Cawthron
Tessa Mayhew


4th Floor, 49 St James's Street, London SW1A 1AH.
TEL +44 (0)20 7499 8122
NELLEN is authorised and regulated by the Solicitors Regulation Authority SRA No: 72911.