Philip Hammond tried to reassure worried companies that a transition deal would be signed quickly

Britain’s hope of securing a post-Brexit transition deal with the European Union is running into trouble amid growing anxiety among business groups that it will be completed too late to be useful.

Theresa May hoped to be able to sign an “implementation period” that keeps the relationship all but identical for up to two years. However, ministers are being warned that this could be imperilled by the status of 975 global deals struck by the EU with countries outside the union.

Britain ceases to be a legal part of these agreements from Brexit day in March 2019.

Some 63 of those deals are free trade agreements; the rest are nuclear accords and agreements on savings, antitrust rules, public procurement, financial services, processed agricultural products, combating