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
The Met Office is warning of persistent heavy rainfall in western Scotland possibly leading to localised flooding.
The family of a World War One hero whose bravery won him a Military Cross have condemned thieves who stole the medal from a cathedral.
Scottish leader Johann Lamont's resignation highlights the post-referendum divisions.