THE UK government will not withdraw funding for the M4 relief road if the proposed black route is rejected, according to a spokesman for the Wales Office.

Newport West MP Paul Flynn previously warned that the UK government will take back £500 million worth of funding for the project if the blue route is chosen.

However, a spokesman for the Wales Office denied this and, echoing Prime Minister David Cameron's comments on the matter, urged the Welsh Government to "get on with it".

He said: “The position is that nothing has changed over the relief road, it is down to the Welsh Government.

“To select the route and funding is not conditional on the route. As the Prime Minister said last week, it is now down to the Welsh Government to get on with it.”

Work is due to start on the project in 2018, but there have been doubts about whether the £1.2bn black route will be selected as Labour did not get a majority in the Assembly elections.

The blue route, which is supported by Plaid, is a cheaper alternative. It is a dual carriageway which uses a combination of the A48 Southern Distributor Road and the former Steelworks Road through the centre of Newport.

However, Mr Flynn has predicted that Newport will become a "traffic hell" if the alternative blue route is chosen and believes it will add to the city's air pollution.

He said: “The matter will be vulnerable to future austerity cuts which will come. I think we’ve got to stand united on this and find that the blue route is not a solution.

“There must be no deal with Plaid Cymru that’s based on inflating gridlock and intensifying air pollution in Newport.

“The black route will disperse the pollution over a wider area. The blue route will concentrate it, certainly in Newport.”