It is the final “base load” contract of work to keep its water pipes, sewers and other facilities across London and the Thames Valley up to scratch between April 2010 and March 2015.

In all, contracts worth up to £1.3bn were let for AMP5. Other framework consortia are:

• Optimise (J Murphy & Sons/Clancy Docwra/Barhale/MWH) for north London and Thames Valley water pipes and sewers;

• MGJV (Morrison Utility Services/Galliford Try) for south London water pipes and sewers;

• GBM (Galliford Try/Biwater/Mott MacDonald) for north and south London water and sewage treatment works.

Martin Baggs, Thames Water’s chief executive, said: “Our operational performance is better than ever right now – best-ever water quality, best-ever sewage works compliance and leakage down 24% in the past four years.

“Our new approach will help us build on these standards of excellence over the next five years.”