Boris Johnson is adamant the Brexit transition period will close at the end of December, despite the risk of the Covid-19 crisis disrupting negotiations, his spokesman has said.

Face-to-face talks which were to take place in London next week had been called off as a result of the outbreak, with officials exploring possible alternatives, such as video-conferencing.

When Johnson’s spokesman was asked whether the status quo transition period might need to be extended as a result, he said simply: “No”, then added: “In UK law, a request for an extension is not possible”.

When the government passed the EU withdrawal agreement in December, it added a commitment that the transition period would not be lengthened.

Pressed on whether that meant the government was prepared to leave without a trade deal if the negotiations were interrupted by virus prevention measures, the spokesman said: “It will be possible to do the trade talks. Both the UK and the EU are fully aware of the timetable which we’re working towards.”

He said both sides had committed to finding alternative ways to continue the negotiations, and were working closely together to achieve this.

“The discussions can take place using an alternative forum, such as video-conferencing,” he said. “Video-conferencing is something which is used throughout the world, and business.”

The government still expected to share a draft agreement with EU negotiators before the next round of talks, he said.

The negotiations, led by Johnson’s EU adviser, David Frost, involve more than 100 officials. During the transition period, the UK remains subject to EU rules and institutions, and continues to pay into its budget. This is to be replaced at the end of the year with an agreement on the future relationship, including on trade and security.

Despite the prime minister’s warning on Thursday that many more families would lose loved ones to Covid-19, the government has eschewed some of the more draconian measures in place in other countries.

Parliament has remained open, and Johnson’s spokesman said local elections in May were also expected to go ahead, despite a request from the Electoral Commission on Thursday for a delay.

In a letter to the government, the commission said holding the elections would put unnecessary pressure on local authorities already having to deal with the public health crisis.

“The risks to delivery that have been identified are such that we cannot be confident that voters will be able to participate in the polls safely and confidently, nor that campaigners and parties will be able to put their case to the electorate,” it said.

However, Johnson’s spokesman said that, for the moment, “we are working to facilitate the local, mayoral and police and crime commissioner elections on 7 May. We continue to work closely with those delivering the elections, while being led by evidence.”

Local elections were postponed in 2001 because of the foot-and-mouth outbreak that affected many farms.