Berwin Leighton Paisner (BLP) has lost the head of its water focus group with the departure of City partner John Hurdley to Bircham Dyson Bell.

The news comes after the news, reported by Legal Week, that BLP in set to complete a deal that will see Thames Water transfer the bulk of its in-house legal team to the City law firm. However, BLP stated that Hurdley's departure was unrelated to those developments.

Hurdley has acted for clients including Bournemouth and West Hants Water, Cambridge Water, Portsmouth Water and Sutton & East Surrey Water.

Following the departure, Thames Water relationship partner Patrick Somers will take over as head of the water focus group.

BLP's Thames deal, which will be worth around £5m a year for the next five years, will see the firm take on 13 of Thames Water's in-house legal team and three administrative staff to carry out all of the longstanding client's legal work.

Hurdley's departure is the second from BLP to a smaller firm this year. In March, City employment partner Paul Mander left to join Dawsons Solicitors.

However, BLP also added a number of partners in London, including new derivatives partner James Duncan, who was previously a counsel with Linklaters, and competition partner Andrew Hockley, who was a senior in-house lawyer with BP. They joined in January and February respectively.