MPs from the Commons public accounts committee have called for the Department of Transport to provide more detailed evidence to support the estimated £50 billion investment. Presenting the committee's findings, chairperson Marget Hodge said:
The pattern so far has been for costs to spiral - from more than £16 billion to £21 billion plus for phase one - and the estimated benefits to dwindle.
In my committee's experience, not allowing enough time for preparation undermines projects from the start.
More top news
Drinking three to five cups of coffee a day could reduce the risk of clogged arteries and thus heart attacks, a study has found.
There are five million British expats across the globe. Many have a vested interest in May's election and many still have the right to vote.
Abba's Bjorn Ulvaeus has a boyish enthusiasm for the cashless society - and he has a challenge for ITV News viewers.