Prime Minister Theresa May needs to speed up negotiations with the European Union, business leaders told her yesterday, amid concern Britain will crash out the world’s biggest trading bloc without a deal.

Slow progress in the talks with the European Union has unsettled businesses and drawn warnings that unless a transition is agreed soon, some may begin activating Brexit contingency plans – which may include moving out of Britain.

Ms May had invited 15 business groups from Britain and continental Europe for talks in her Downing Street office to urge them to back her Brexit strategy and persuade companies not to move overseas.

We now need to move beyond warm words if jobs and living standards are to be protected

The executives told Ms May she needed to provide more clarity on three issues critical for talks to progress: negotiating any potential exit bill, settling the rights of EU citizens living in Britain, and arrangements for the border in Ireland.

“Business is extremely concerned with the slow pace of negotiations and the lack of progress,” said Emma Marcegaglia, president of BusinessEurope, a lobby group that speaks for companies in European countries, including Britain.

Ms May wants to agree with the EU the broad outline of a so-called implementation period of around two years after Britain’s exit from the EU in March 2019. During that period, its access to the European Union single market would remain largely unchanged while new arrangements were put in place.

International companies have become increasingly vocal in recent weeks over fears that Britain will leave the EU without a trade deal, a move that would send shockwaves through global markets and fracture some supply chains.

Carolyn Fairbairn, director general of the Confederation of British Industry, said all the businesses at the meeting warned Ms May about the damage leaving without a trade deal could do.

“We now need to move beyond warm words if jobs, investment and living standards are to be protected,” she said.

Talks between Britain and the EU are currently deadlocked.

The European Union told Britain last week to spell out what it will pay Brussels when it leaves the bloc in 2019 or face more delay in talks on future trade ties that are vital for business.