The group, which included former cabinet minister Stephen Crabb, Northern Irish DUP deputy leader Nigel Dodds and Welsh Labour’s Stephen Kinnock, urged May to approve the third runway, describing it as “our gateway to the world”.

Reports have suggested that the prime minister is not in favour of a compromise that could see both Heathrow and Gatwick building new runways, the BBC said.

In the group’s letter to May, the politicians argued:  "Although Heathrow is in London, it is the UK’s hub airport.

"Other countries are investing in and supporting their hub, or looking on enviously as they hub through other countries.

"Northern Ireland, Scotland and Wales all have our own successful and growing airports.

"But Heathrow is our gateway to the world, bringing tourists to our attractions and helping our exporters reach new markets.

"Whether we are connected by road, rail or air, we know that connections to Heathrow are a key driver of investment decisions.

"Expanding Heathrow will create nearly four times more jobs in our three nations than other options being considered."

A decision on airport expansion is expected to be announced this week, with rumours circulating it may even be tomorrow.

May faces notable opposition to expansion at Heathrow, both within her own cabinet as well as the Conservative party as a whole.