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.
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Two pilots have been arrested on suspicion of being under the influence of alcohol as they prepared to fly from Scotland to the New York.
Two teenagers have been arrested on suspicion of drugs offences following the death of a 17-year-old youth who collapsed at Leeds Festival.
Theresa May will gather Cabinet ministers together on Wednesday to discuss her plans for Brexit.