Thousands of lorry drivers will spend Christmas Day stranded at the border with the English Channel with some likely to have spent five nights in their vehicles.

A chorus of beeping horns sounded at the Port of Dover on Christmas Eve as those at the front of the queue celebrated finally being able to leave – but many more are expected to be stuck there until at least Boxing Day.

Fewer than 100 vehicles left the port on Wednesday night, but a spokesperson said that as testing continued, departure numbers would “rise significantly”, though they could not provide figures for Thursday.

Because of the more transmissible coronavirus variant in the UK, French authorities said hauliers must return a negative result from a test carried out within the past 72 hours before being allowed to leave.

Some 2,367 of an estimated 6,000 drivers had returned negative coronavirus tests by Thursday afternoon, while three tested positive, according to Transport Secretary Grant Shapps.

Mr Shapps said the border at Dover, the Eurotunnel and Calais would remain open “throughout Christmas” to get hauliers cleared “as soon as possible”, with the help of 10,000 more tests brought by 26 French firemen drafted in on Thursday.

Traffic is moving more quickly at the Eurotunnel, where more than 1,000 vehicles left on Wednesday night, with around 2,000 more expected to depart by the end of Thursday, but many will remain there for Christmas Day, according to Duncan Buchanan, a policy director at the Road Haulage Association (RHA).

Mr Buchanan said: “The most reassuring thing is that food is getting through at Manston, and I have to say a big thank you to everyone who volunteered to help drivers stick it out in cold conditions in the days leading up to Christmas.”

Imran Nisar, a project leader at the Muslim charity Al-Khair Foundation, which prepared over 400 lunches for the drivers, said: “We plan to keep delivering until all the truckers have gone home – even on Christmas Day if necessary.

“Some of them don’t even have water in their cabs so these supplies are making a big difference to them and also raises their morale.”

Volunteers from the Salvation Army, Sikh communities and other groups have also helped keep the drivers going.

The leader of Kent County Council, Roger Gough, expressed his “deep sympathy” for the drivers, adding that the council would be providing extra portable toilets, food and water for them.

He said: “The kindness and humanity shown by people who have rallied to provide welfare for those caught up in delays at the Port of Dover and Eurotunnel is amazing.”

Mr Buchanan blamed the French government for the situation, saying that testing hauliers for coronavirus was a “ridiculous restriction”, adding it was “an outrage that they are doing this to the drivers of Europe who just want to get on with their jobs and get home for Christmas”.

The RHA’s boss Richard Burnett agreed that France was treating drivers like “pawns in a larger game” in the build-up to the Brexit deal – an allegation the French have repeatedly denied.

He told the BBC that lorry drivers’ rates of coronavirus infection were much lower than those of workers in other sectors, at between 3% and 6%.