Business leaders representing 500,000 companies have urged prime minister Theresa May to table a vote on expansion at Heathrow.

They have signed a letter calling for action on a third runway at the London hub.

The move follows an open letter sent by the five leaders of the UK’s largest trade unions calling on Parliament to back Heathrow expansion for the jobs and growth it will create across the country.

The letter to Number Ten has been signed by the heads of the Confederation of British Industry, the British Chambers of Commerce, the Institute of Directors, the Federation of Small Businesses, the EEF – The Manufacturers’ Organisation, the London Chamber of Commerce and Industry, and airport expansion lobby group London First.

The groups warn: “As Brexit approaches, Heathrow expansion is crucial to making sure the UK remains an outward looking trading nation and is well-equipped to compete on the world stage.

“For British businesses, the benefits of expansion have always been clear: connections to new markets and trading opportunities, with better links with regional airports across the UK a boost to British exports, and a skills legacy for future generations.

The letter adds that rival European hubs such as Frankfurt, Amsterdam Schiphol and Paris Charles de Gaulle are pulling ahead at the UK’s expense.

“There are many unknowns for businesses surrounding Britain’s future trading arrangements, but what is absolutely certain is that our economic success depends on securing Heathrow’s future as a leading international airport.

“As the UK’s only major hub airport it is a vital trade link for our members, and it has never been more important to develop our infrastructure, our businesses and our skills,” according to the letter.

“Heathrow expansion will strengthen such existing connections and add up to 40 new ones, linking Britain’s exporters – large and small – with customers and opportunities around the world.

“It’s not just exporting businesses that stand to benefit. Across the UK, expansion will create tens of thousands of jobs – most outside London – and 5,000 new apprenticeships.

“Even before it opens, the process of building the new runway will bring massive benefits to construction businesses all over the UK, helping develop the skills that businesses need in a post-Brexit Britain.”

Without expansion, “the risk is that over time British businesses will be denied the increased cargo capacity and long-haul routes we need”.

The government is due to timetable a vote on the Airports National Policy Statement, which will set out its airport infrastructure policy – including Heathrow expansion – in the first half of the year.

The vote is expected to happen before the summer recess, which runs from July 24 to September 4.