Westminster stalwart Bircham Dyson Bell has beaten City competition to land a lucrative contract advising Thames Water on the construction of a new reservoir on the Upper Thames.

The firm, which posted a 21% increase in turnover last year, scored the work despite Thames Water frequently instructing major practices including Linklaters, Allen & Overy and Slaughter and May.

Thames Water also has a string of top 50 UK firms on its panel, including Pinsent Masons and Osborne Clarke.

The multi-million pound project is the first major instruction from the client for Birchams' projects team, which is currently advising on several high-profile schemes including the P&O London Gateway International Port regeneration project.

Projects partner Nicholas Brown is spearheading the Birchams team working for Thames Wate. Alongside him is planning partner Mark Challis, who joined the 44-partner firm from Norton Rose in 2003.

Thames Water is owned by German-based RWE Group, the third largest water services company in the world, which also owns UK stable-mate RWE npower.

In February, the two sister companies completed a major review of their advisers and combined their respective legal panels.

The change followed the promotion of Caroline Farebrother as the combined legal department's head last year. She said the move was designed to improve the depart-ment's relationship with its advisers and to leverage its buying power.