Eight contractors are rumoured to be vying for a £1bn Thames Water AMP5 framework.

BAM, Black & Veatch, Costain, a joint venture between Galliford Try and Biwater, Interserve, Laing O'Rourke, Skanska and Veolia are all hoping to be on the framework, which forms part of the Thames Water's qualification system, known as The Register.

The contract will include the design and construction of sewage treatments, water treatment works, pumping stations and reservoirs.

The contracts have been split between three operational areas: North London, South London and Thames Valley. Contractors who make their way onto the register will be required to compete for work, which will take place between 2010 and 2015.

Thames Valley has made no comment on who is bidding for the framework.