Thames Water has written to the industry regulator Ofwat to ask permission to charge customers an addition one-off fee of about £29 per household. The firm, which made £150m profit last year, has blamed "unquantifiable" costs.
The Lib Dems deputy leader Simon Hughes has called on the water regulator Ofwat to reject a request from Thames Water to raise their prices to pay for the Thames Tideway Tunnel.
A spokesperson for the Liberal Democrats confirmed that the party would present an alternative method of paying for the Thames Tideway Tunnel later this month.
Britain's biggest water company appeals to the water regulator to be allowed to charge its customers an extra £29 on top of their bills.
Thames Water made profits of £150m last year, and gave shareholders £92m - so why is it wanting to charge customers an extra £30?