Construction group Galliford Try has won a contract worth up to £500m with Thames Water to upgrade water and waste water treatment facilities in the London region.The work will be carried out in a joint venture with engineering and development consultancy Mott Macdonald, water treatment group Biwater and Morrison Utility Services.The work, which will be done as part of the 5 year investment programme (Asset Management Period, AMP5) Thames, along with other water companies, agreed with the regulator, will initially be worth £100m, but could potentially rise to £500m.'We are delighted to extend our relationship with Thames Water as one of its delivery partners,' said Galliford Try chief executive Greg Fitzgerald. 'This appointment adds to the AMP5 frameworks we have already renewed with five other water clients and underlines our position as a leading contractor to the UK water industry.'