MPs voted to approve a government concession which aims to cut the dumping of raw sewage into the UK's rivers and sea.

The government says its proposal will legally require water firms to make a “progressive reduction” in dumping raw sewage into waterways.

But critics say the move does not require water companies to take action quickly enough, allowing dumping to continue for years to come.

The government put forward its own amendment to “redraft” one put forward by the Duke of Wellington in a Commons vote on Monday evening.

Environment minister Rebecca Pow told the house it would now put a “direct legal duty” on water companies to secure a “progressive reduction in the adverse impact of discharges from their storm overflows”.

She said: “Our amendment will ensure that they have to take the necessary steps relative to the size of the problem.

"If we do not see sufficient progress from water companies, Ofwat and the government will be able to take enforcement action and we will not hesitate to do this.

“And not only that, under the other provisions in this Bill, the OEP (Office for Environmental Protection) will be able to take enforcement action itself against the Environment Agency, or Ofwat, or indeed the government, should it feel that any of us are not adequately discharging our duties.”

MPs voted 283 to 163 with a majority of 120.

Labour shadow environment secretary, Luke Pollard, said the government had been “shamed” into a U-turn on sewage but added the amendment did not go far enough.

Mr Pollard said: “The amendment the minister has cited in lieu of the Duke of Wellington amendment is confined to storm overflows and not the sewage system as a whole.

“There’s no specific duty on Ofwat or the Environment Agency to ensure compliance – and there should be – and we need to have a focus on reduction on harm rather than adverse impacts. This looks like looking busy without making a real difference.”

Following the vote, Caroline Topping, Green councillor for Beccles and Worlingham on East Suffolk Council and a Suffolk County councillor criticised the bill for not setting targets including specifying the amount of sewage dumped into waterways and timescale.

She said: "It is incredible that this is the first time a government has tackled the water companies about storm overflows.

"Whilst these water companies shareholders have made huge profits from years of under investment which is now needed and are saying this will fall upon customers to pay for.

"This bill has been over two years in the making and we are still unsure when it will actually be passed.

"In the meantime water companies can continue to use their storm overflows to discharge raw sewage into our rivers and seas."

She continued: "Also it was said that a review of the scale of fines on water companies needs to be carried out.

"An organisation called the Office of Environment Protection (OEP) is to be set up but will be a small organisation who can scrutinise Government, the Environment Agency and OFWAT. But how much funding is this organisation to be given in order to carry out its duties properly?

"The EA and OFWAT have powers and need to use their teeth against water companies and enforce against pollution.

"We have no idea when the bill will be passed. It is not strong enough with progressive reduction being too weak. There are no targets or timescales set and potentially an underfunded small organisation being set up to enforce action."