A FUNDING row between Westminster and Cardiff Bay is threatening to derail electrification of the train network in the Welsh valleys, transport union RMT warned yesterday.

The £850 million modernisation project is headed for the buffers as the two governments argue over who should foot the bill — though Prime Minister David Cameron is on record saying Whitehall would cover the costs.

The union said it was sick of “political point-scoring” and called for urgent action to end the stand-off over the commuters lines serving Cardiff and Swansea.

RMT acting general secretary Mick Cash said: “The trail on all of this goes right to the heart of the Westminster government who seem to be prepared to renege on commitments to rail improvements and modernisation at the drop of a hat.”