Britain and the EU are facing calls to back away from a “game of chicken” and extend the Brexit transition period immediately, as both respond to the coronavirus pandemic.

Boris Johnson, however, has insisted there will be no change to the transition period – during which the UK follows EU regulations, including its free movement laws. It is scheduled to finish at the end of the year.

However, with parts of Europe in lockdown and the UK government expecting the peak of the crisis in Britain in late spring and early summer, some experts are calling for immediate agreement to delay.

There are concerns that the peak of the disease in the UK could coincide with critical negotiation deadlines. June is the final month for Britain to ask for an extension beyond this year.

Trade expert David Henig is among those calling for a rethink. “I don’t see how you can realistically, by the end of June, make a decision on how trade talks are going,” he said. “You would be doing it with a lot of people under pressure, dealing with something that really is an arbitrary deadline. This is the classic force majeure cause – an unforeseen circumstance of the extreme degree.

“This should apply to both sides. The Italians are practically completely in lockdown. They have stopped having all but essential meetings in Brussels. It’s a bit of a game of chicken, with neither side wanting to say they can’t cope with it. An extension could be offered on whatever strict terms.”

He also warned the EU that there were signs that its response to the latest round of talks was not as effective as its approach to Britain’s EU divorce deal, finally voted through parliament earlier this year. “The commission are going through the ‘difficult second album’ phase this time round,” he said. “Last time, they were undoubtedly the grown-ups in the room. It’s less clear that that applies this time.”

Matthew O’Toole, a former adviser to Theresa May who is now an SDLP politician in Northern Ireland’s assembly, agreed. “Right now, I’m loth to even mention Brexit,” he tweeted. “But, as of today, the UK government is still ruling out extending transition. That is lunatic. The world will soon be recovering from a huge economic shock. No one – not the EU or even Trump’s US – will have time for Brexiter fantasies.”

Face-to-face talks, due this week in London, have already been cancelled amid the crisis. Other methods of remote communication are being used. Initial plans suggested there would be five rounds of talks by mid-May, before a crucial summit in June.