Michel Barnier has said the European Union remains “determined” and “patient” in its bid to strike a post-Brexit trade deal with the UK as crunch talks resumed in Brussels.

The EU’s chief negotiator and his British counterpart Lord David Frost are continuing negotiations with just over six weeks to go until the end of the transition period.

The talks, which follow a similar round in London last week, come ahead of a European Council video summit on Thursday which has been touted as a deadline for a draft deal.

Mr Barnier tweeted on Monday morning: “With @Europarl_EN & all Member States, we remain determined, patient, respectful.

“We want our future cooperation to be open but fair in all areas.”

Lord Frost said on Sunday evening that there had been progress in a “positive direction” in recent days.

“We also now largely have common draft treaty texts, though significant elements are of course not yet agreed,” he wrote on Twitter.

“We will work to build on these and get an overall agreement if we can.

“But we may not succeed. Either way, as the Prime Minister @BorisJohnson made clear on 16 October, people and businesses must prepare for the change that is coming on 31 December, most of which happens whether there is a deal or not.”

The UK formally left the European Union in January, but will continue to follow the bloc’s regulations until the end of the year.

If no agreement is in place at the end of December, goods travelling between the two parties will be subject to tariffs set out by the World Trade Organisation.

The issues which are still to be ironed out are thought to include the ongoing row over fishing rights, how any deal between the two parties would be governed, and the “level playing field” measures aimed at preventing unfair competition on issues including state subsidies.

Deadlines imposed on a future agreement have proven to be soft in the past, with Mr Johnson saying in September: “There needs to be an agreement with our European friends by the time of the European Council on October 15 if it’s going to be in force by the end of the year.

“If we can’t agree by then, then I do not see that there will be a free trade agreement between us, and we should both accept that and move on.”

The mid-October deadline appeared to be scratched at the start of that month, when Downing Street and European Commission president Ursula von der Leyen agreed to intensify talks during a video conference call, acknowledging “significant gaps remained” between the UK and Brussels.

Any deal struck would be subject to ratification by EU member states, the European Parliament and the UK Parliament, meaning time is tight.

The agenda for Thursday’s meeting of 27 European leaders does not mention Brexit, with the response to the Covid-19 pandemic instead taking centre stage.

But with only one other meeting – between 10-11 December – scheduled before the end date of the transition period, this could be seen as a key moment in the shaping of the UK’s departure.

European Commission spokesman Eric Mamer played down the impact Mr Johnson’s coronavirus self-isolation would have on the talks, pointing out that he had been in phone contact with Ms von der Leyen throughout the process.

“We wish the Prime Minister well. We know how difficult it is for leaders to continue to conduct business in the current circumstances,” he told reporters in Brussels.

“There are and there have been regular contacts in any case by phone between the president of the commission and the Prime Minister, so I’m sure they will continue to have these contacts.”

Ireland’s foreign affairs minister Simon Coveney said on Sunday a deal was “doable”.

“I think I would sum it up by saying this is very difficult, but, it’s also very doable.

“And I think the consequences of not getting a trade deal and a future relationship deal … before the end of the year, I think is very significant.”