In any decision of the magnitude of HS2, understanding of the costs and benefits involved will evolve. Politicians should not be afraid to think again about a project whose estimated cost has just risen again by a quarter, to £42.6bn. In 2010, when the then Labour government decided to back HS2, we did so based on the best estimates of what it would involve. But these were almost entirely speculative. The decision was also partly politically driven. In addition to the projected cost, we gave insufficient attention to the massive disruption to many people's lives construction would bring. Why? Not because we were indifferent but because we believed the national interest required such bold commitment to modernisation. Read more