Boris Johnson is facing fresh pressure to delay the end of the Brexit transition period as countries focus on battling the coronavirus epidemic.

MEPs from the largest grouping in the European Parliament warned that the British economy would face the “double whammy” of coronavirus disruption and a possible no-deal Brexit if the prime minister presses ahead with the 31 December deadline.

Extending the transition period is “the only responsible thing to do”, as the timetable to hammer out a trade deal between the UK and the bloc is too tight, warned the centre-right European People’s Party (EPP).

No 10 rebuffed the calls, saying the date was “enshrined in UK law” after the withdrawal agreement bill cleared parliament earlier this year.

But talks have ground to a halt as both the UK and the EU’s chief Brexit negotiators have been diagnosed with coronavirus and officials have been diverted to work on curbing the outbreak.

A recent Focaldata poll found that two-thirds of people in the UK (64 per cent) want the government to request an extension to the transition period.

Christophe Hansen MEP, a negotiator on the parliament’s international trade committee, said: “Under these extraordinary circumstances, I cannot see how the UK government would choose to expose itself to the double whammy of the coronavirus and the exit from the EU single market, which will inevitably add to the disruption, deal or no deal.

“I can only hope that common sense and substance will prevail over ideology. An extension of the transition period is the only responsible thing to do.”

German MEP David McAllister, who chairs the UK coordination group in the parliament, said the EU was open to extending the transition but the “ball is now clearly in the British court”.

He said: “The United Kingdom would have to submit an official request. So far, the UK government has constantly rejected such an option.

“Under the current circumstances, London should carefully re-examine a prolongation.”

Asked if the UK would seek a delay, the prime minister’s official spokesperson said: “The transition period ends on 31 December 2020. This is enshrined in UK law.”

No representations have been received from EU member states over an extension, the spokesperson said.

It comes as Michael Gove, the cabinet office minister, was set to hold a video call with European Commission’s vice president Maros Sefcovic over implementing the UK’s withdrawal agreement.