Britain is in danger of signing up to poor-quality trade agreements that do not benefit the economy and will not command the support of the public after Brexit, a group of leading UK trade experts have warned.

In an open letter to The Telegraph, the group of 14 trade policy academics, think-tank specialists and industry advisers fire a warning shot across the bows of Boris Johnson for setting “arbitrary deadlines” to seal a trade with Europe by the end of next year.

“The engines are being revved towards striking new FTAs [free trade agreements] by arbitrary deadlines, with little sense of what we actually want to achieve,” said the group, lamenting the “poor quality” of debate in the current election campaign over trade.

The signatories include David Tinline, the former senior adviser to the WTO director-general, Professor Alan Winters of the UK Trade Observatory, and Allie Renison of the Institute of Directors as well as several former UK and Australian trade officials.

They issued their bipartisan letter after Mr Johnson made it a manifesto commitment on Sunday not to extend the Brexit transition period, leaving just 11 months for the UK to finalise a trade deal with Europe.