DAVID Cameron said he was proud to have "unblocked" work towards electrification of the Valleys railway lines.

The prime minister is at the Celtic Manor in Newport this afternoon where he has unveiled a funding package which will see the UK Government contribute £125 million to the Valley Lines electrification scheme, while also covering the full costs of electrifying the Great Western mainline to Swansea.

Mr Cameron said: “I’m proud to have played a part to unblock the blockage [on electrification of the Valleys railway lines].

“We are digging deep to make sure this goes ahead. You’ve got to think of the Valleys communities that have had these railway lines that historically were based on coal and so weren’t really about helping to move people rapidly so they can be more connected for work purposes and all the rest of it.

“It’s an important investment. I think now we’ve done a deal we should shut up about it. But I think any independent adjudicator would accept that the UK government has bent over backward to be generous and to try and find a way through this and to provide as we have done today over £100m of capital funding.”

He said he hoped the potential for an M4 relief road would not stall in legal wrangling: “The money is there which is the important thing, so the project has been unblocked as it were. But now it’s up to the relevant authorities to get on and do what’s needed. I hope it won’t get blocked.”

As to whether Wales could increase its borrowing powers, he said he wanted Wales to gain tax raising powers after a referendum.

Welsh Secretary Stephen Crabb added: “There’s one easy way to increase the borrowing available to the Welsh Government and that’s if the Welsh Government crack on and have the referendum and have income tax devolved down. That unlocks a whole tranche of new borrowing powers to Welsh Government.”

Shadow Welsh secretary Owen Smith, whose Pontypridd constituency is served by the Valley lines, said: "David Cameron has been doing the hokey cokey on funding the Welsh railways for over a year.

"First he claimed that he'd pay for the lot, including the full line to Swansea and commuter services to the valleys, then he reneged on the deal and claimed the Welsh Labour Government would have to pay instead, and now he appears ready to split the tab.

"Welsh rail passengers will be pleased he's finally made his mind up, even if, in the end, the Welsh Government is going to have to foot some of the bill."