And it will not just be police officers, publicans, water inspectors, charity workers, vicars, firemen, taxi drivers, doctors and hospital staff.
"There are more people working than you would imagine," a spokeswoman for the Confederation of British Industry said. "People think of train and bus drivers, but I don't think any of them are operating. It is the hotels, catering, pubs, utilities, emergency services, lorry drivers and farmers. Since the sales start on Boxing Day we reckon there will probably be people getting the shops ready on Christmas Day."
Both the Labour and Conservative parties have press officers on duty, although a Labour spokeswoman went to great pains to insist: "The Labour Party believes people should have the right to enjoy Christmas."
Jo Moore, 33, the Labour Party press officer who has drawn the short straw, said: "Stories do sometimes break on Christmas Day. Certainly by the evening when the first editions drop there are calls. That's the level of activity. There's isn't anybody actually sitting in Millbank Tower on Christmas Day. They would be a particularly sad individual.
"I will have time to cook my Christmas turkey and open my presents with my kids. I don't think I could explain to my kids if I wasn't at home, but they don't mind the odd phone call."
Some employees are rewarded for their seasonal services. Patrolmen with the Royal Automobile Club have no problem with volunteers - they earn five times their normal wage if they work on Christmas Day. The "Knights of the Road" top the bonus league, picking up pounds 250 a shift. The rival Automobile Association quadruples wages.
To many taxi drivers, Christmas Day is the perfect time to write-off debts. Paul Gould, 52, who works for Computer Cab, a London-based company, pays for all his Christmas presents by working three or four hours on the 25 December.
"The account work is very lucrative," he said. "Computer Cab almost invites you to go out, the incentives are that good." Besides the fact that the meter clocks up pounds 40-pounds 50 an hour, Mr Gould is glad of the excuse to get out of the house. "Christmas morning is crazy," he said. "I like to get out of the way. My wife's got a lot to do."
Pat Bailey, who also works for Computer Cab, takes a different view. No amount of pound signs could tempt him away from his turkey. "Not under any circumstances whatsoever," he said. "It's a day to be with my family and friends. The way I look at it is that I work very, very hard the rest of the year. If I can't do that little bit extra during the year there must be something wrong with me."
But extra pay is out of the question in some cases. At the telephone bank, First Direct, employees are expected to hunker down willy nilly. The service is, after all, round the clock, 365 days a year. And the bank gets the custom. It expects an incredible1,200 people to interrupt their turkey to make a call on Christmas Day.
Last year, the company received 120 calls from customers who just rang to say "Happy Christmas" on Christmas Day. Most were from people trying to make last-minute financial arrangements, such as asking for an overdraft or a Visa extension, or trying to transfer funds. The staff is dedicated from the top downwards: even the chief executive "pops in to say: `hi'," one member of staff reports.
According to a survey by the Institute of Management, those who work for small companies are more likely to benefit from an extended break during the holiday period. Seventy per cent of managers in small firms - those comprising one to 100 employees - said that their organisation took time off, compared with 45 per cent of managers in large firms.
Roger Young, the institute's director general, said: "Christmas, in particular, is an ideal time opportunity for hard working teams to let their hair down and get their knees up at the end of the year. Staff will then approach the New Year invigorated and remotivated."
Journalists and television staff also have to work. In 1979 Martyn Lewis remembers being called up by ITN in the middle of Christmas lunch and told to hop on a plane to India because the Soviet Union had just invaded Afghanistan.
This year Mr Lewis will spend Christmas Day rattling around the BBC television studios from dawn to dusk. Why him? "It was basically my turn," he said. "I've been at the BBC 10 years and I'd always found a very good reason not to do Christmas Day. I ran out of excuses, basically."
The British way, page 11