British business leaders are calling on the government to rescue Eurostar, which has said it is close to collapse following restrictions to contain new COVID-19 variants.

Until recently a symbol of easy high-speed rail travel in Europe, Eurostar has been crippled by the coronavirus crisis, with its platforms and facilities in Paris, London and Brussels now eerily quiet.

Eurostar is currently running just one service a day between Paris and London – a far cry from before the pandemic, when it would operate two trains an hour during peak times.

The London First lobby group said Eurostar needed "swift action to safeguard its future," in a letter sent to Finance Minister Rishi Sunak and the Department of Transport.

The missive, signed by leaders from 28 UK businesses, warned the UK Treasury and Department for Transport not to let the firm "fall between the cracks of support." It said the company could run out of funds in the coming months.

Last week, Eurostar – majority owned by French firm SNCF – reported services were down 95 percent from the previous year.

"The company is in a critical state, I'd even say very critical," said Christophe Fanichet, who heads SNCF Voyageurs, the passenger unit of the network.

Fanichet said the problem for the London-based group was that it was seen as French by the British government and as British by the French, meaning it had been difficult to secure bail-out cash.

"Given the passenger numbers, it's a group that has been hit more than airlines," he added.

Travel restrictions continue to be tightened, with France now requiring UK arrivals to observe a seven-day quarantine and undertake a COVID-19 test at the end, while Britain has also introduced new quarantine measures. 

The joint letter highlighted how important it is to maintain the high-speed rail link.

"Eurostar is not asking for special treatment. We urge you to ensure that they have equal access to financial support as companies in similar positions – at the very least this should include business rates relief and access to government loans," it stated.

"Maintaining this international high-speed rail connection into the heart of London has never been more important. Having left the European Union, we need to actively set out our stall as an attractive destination for people to live, work and play.

"Safeguarding the future of this connection to the continent should be a symbol of both our desire to build back better and our new cooperative relationship with our European neighbors."

A spokesman for the Department for Transport told the BBC: "We recognize the significant financial challenges facing Eurostar as a result of COVID-19 and the unprecedented circumstances currently faced by the international travel industry."

He added the government had been in contact with Eurostar "on a regular basis" since the start of the coronavirus crisis and would continue to work closely with the firm.