Government cautiously optimistic on Heathrow vote, says Grayling

Transport secretary claims strong support across political spectrum for third runway

The government is "cautiously optimistic" about winning a key parliamentary vote on the expansion of Heathrow airport, the transport secretary, Chris Grayling, has said, defending the controversial idea as being good for the whole of the UK.

The Conservatives, who have a three-line whip in place for their MPs, are likely to get significant Labour support in the vote on Monday after Unite called for Labour MPs to back the third runway.