Britain on Tuesday launched a ?1.0 billion support package for Covid-hit businesses, as staff absences from rising cases began to bite in the run-up to Christmas.

Finance minister Rishi Sunak said some 200,000 firms would be eligible for one-off grants to offset losses from what is normally the busiest time of year.

Pubs and restaurants have seen Christmas parties and bookings cancelled because of the spread of the Omicron variant of the virus, hitting December trade by as much as 60 percent.

Sunak said the government recognised that businesses in the hospitality and leisure sectors were facing "huge uncertainty at a crucial time".

The government is banking on an ambitious campaign to get all adults in England to have a booster jab of a Covid vaccine by the end of December to try to stop the spread of the mutation.

The director of the Wellcome charitable foundation, Jeremy Farrar, told BBC radio transmission was "eye-wateringly high", as daily infection rates nudged towards 100,000.

But unlike governments in some of Britain's nearest neighbours on the European mainland, Prime Minister Boris Johnson has ruled out immediate curbs in the run-up to Christmas.

Tighter public health measures could yet be introduced after this weekend, according to media reports.

Across the country, all sectors of British industry have been hit as staff contract the virus and are forced to self-isolate at home.

As the Christmas getaway begins, train companies apologised for employee absences and warned they could affect scheduled services and even lead to cancellations.

Edinburgh Castle and the National History Museum in London -- two of the country's most visited attractions -- were forced to close their doors because of staff illnesses.

That came after several theatres in London's West End entertainment district cancelled performances to protect performers and the public.

The hospitality and retail sectors have been hard hit as people stay home and staff get sick The hospitality and retail sectors have been hard hit as people stay home and staff get sick Photo: AFP / Justin TALLIS

Meanwhile, the hotel and restaurant industry has seen closures because of a lack of staff.

And in the public sector, the government has called for retired teachers to help out, as the virus forces staff out of the classroom.

In London, unions have warned that firefighters face "unprecedented" manpower shortages, although its response to emergencies has not yet been affected.

Johnson has come under pressure from business owners and industry bodies to reintroduce support packages for Covid-hit sectors, who were already struggling after curbs in the last year.

He is, however, facing intense pressure from within his own ruling Conservative party not to bring in tougher restrictions on public freedoms.

Last week, nearly 100 of his own MPs voted against the roll-out of vaccine passports to allow access to some venues, including sports grounds.

Twelve months ago, Johnson was forced to impose restrictions on indoor mixing and social distancing as the Alpha variant of the virus spread rapidly, putting hospitals under pressure.

But it has since been claimed that he and his own staff broke the rules by holding parties at Downing Street and across government departments.

Retailers have felt the chill from Omicron in December, as shoppers stayed at home to prevent catching the virus before Christmas, employers' association the CBI said.

The Confederation of British Industry's lead economist Ben Jones said retail sales had slowed and expectations for January had been downgraded.

"The concern now is the potential for rapidly rising sickness and staff absences to cause renewed disruption to supply chains in the New Year," he added.

The hospitality and retail sectors were already feeling the pinch of staff shortages, as foreign staff left due to the pandemic and new post-Brexit immigration rules.

Last year, the government offered sales tax holidays and cuts, plus emergency loans to keep businesses afloat as trade plummeted due to stay-at-home restrictions.