Chancellor Rachel Reeves has indicated she will overrule environmental objections to a third runway at Heathrow in order to prioritise economic growth, a position likely to bring her into conflict with colleagues including energy secretary Ed Miliband.

Speaking as she began a 48-hour pitch to international investors at the World Economic Forum in Davos, Ms Reeves said she would back infrastructure projects even where they are unpopular.

The expansion of Heathrow has been debated for almost 20 years but despite the consistent support of business groups and a consensus it would boost economic activity, environmental and political objections have prevented it.

Asked directly if she would now put the runway, along with expansion at Gatwick and Luton ahead of the UK’s net zero commitments, Ms Reeves said: “I’m not going to comment on speculation, but what I would say is when the last government faced difficult decisions about whether to support infrastructure investment, the answer always seemed to be no.

“We can’t carry on like that, because if we do, we will miss out on crucial investment here into Britain. You’ve already seen a number of decisions, including on Stansted and City Airport, on energy projects, on transport infrastructure, because we are determined to grow the economy.”

The chancellor’s trip to Davos comes with her economic program under increased scrutiny after a bumpy start to the new year, including a rise in borrowing costs and data showing the economy has stagnated since the election.