The chief executive of High Speed 2, Alison Munro, has dismissed the claim that the rail project will cost £80 billion - more than double the official estimate - as "absurd".
She told ITV News that she "doesn't recognise" the figure allegedly quoted in a report by the Institute of Economic Affairs, and that she is confident the cost will not overrun.
More top news
Some hand-written notes in an ancient manuscript turned out to be the oldest piece of music for more than one voice ever discovered.
Wet weather is expected across most of the UK later as rain sweeps in from the west overnight.
Spoiler alert: This year's Apprentice finalists have been chosen after escaping Lord Sugar's contestant cull.