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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With UK trials of driverless cars underway across the country, worries about the vehicles have been raised following a crash in Florida.
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