'Watch Wales rail electrification cost' says minister

Mr McLoughlin was in south Wales to discuss the benefits of electrifying the railway line in the region

A £1.1bn rail electrification plan for the Great Western line into south Wales may go over budget, a cabinet minister has warned.

Transport Secretary Patrick McLoughlin, campaigning in Cardiff, said the UK government must "keep an eye" on cost as "we've never done this before".

He was visiting to highlight the Tories' role in upgrading the railways.

There was a dispute over whether Wales or Westminster would pay for the major upgrade between Swansea and London.

The south Wales Valleys lines will also be electrified as part of a deal announced by Prime Minister David Cameron in November.

'Value for money'

On Tuesday, Mr McLoughlin told BBC Wales: "We are doing in excess of 850 miles and we are working with the Assembly with the Valleys lines.

"Obviously we need to keep an eye on cost, but I hope as we get on with the job we can keep a control on those costs.

"There will be some cost increases because we've never done this kind of thing before."

Policy guide: Where the parties stand

Mr McLoughlin said electrification plans were "value for money" and stressed that he hoped to meet the 2018 deadline for completion.

Plaid Cymru candidate Jonathan Edwards said the UK government had a "woeful" track record of delivering improvements to infrastructure in Wales.

"The real debate in this election is over fair funding for Wales in the case of England-only projects such as HS2, HS3 and Crossrail 2," he said.

"While Labour and the Tories have wasted time arguing over who foots the bill, Plaid Cymru is the only party showing some ambition for Wales and demand a fair share for our nation from these projects."

A spokesman for UKIP added: "What a surprise - another public sector project over budget.

"This just shows that neither Labour in Cardiff or the Conservatives in London can be trusted to manage the economy responsibly."