Londoners are more in favour of expanding Gatwick than the alternatives says the airport operator, quoting a YouGov poll, the first to be carried out since the UK government once again delayed a decision on the issue.

Gatwick scored more highly than Heathrow on issues such as the effect on air and road congestion, according to the poll.

Some 40% of Londoners would rather see an extra runway at Gatwick compared with 34% at Heathrow and, says Gatwick Airport, is the tenth YouGov poll of Londoners showing Gatwick as the preferred choice.

Gatwick’s location to the South of London means that, unlike Heathrow in the West, it is not surrounded by heavily congested motorways, it says. The airport has never breached legal air quality limits and can guarantee it will stay within legal levels if it expands, argues the operator.

Gatwick chief executive Stewart Wingate said: “Crucially, Gatwick expansion would not lead to illegal levels of pollution and so can actually happen. Momentum is with Gatwick as the debate now firmly focusses on what is best for the economy and the environment.”

In December, the government delayed the expected final decision, which had been widely expected to favour Heathrow, ostensibly to do more work on the environmental impacts of expansion. Commentators say that the delay has opened a fresh window of opportunity for Gatwick to put its case.