So that was Christmas, then, and today is Manic Monday - the day of dread reckoning when we count the terrible toll the festive season has taken on our wallets and our lives, and perhaps do something about it.

As humdrum reality returns, we will be shuffling off the last fortnight's lethargy in a big way, taking our life in our hands and giving it a good shake. It's the day for grasping the nettle of a failed marriage, booking a holiday or starting the search for a new job.

Divorce lawyers are braced for the busiest day of the year, when the strains of Yuletide prove too much for thousands of couples. They call the first Monday after the break D-Day, and expect a deluge of calls from people desperate to untie the knot.

Relate, the relationship support service, receives 50 per cent more calls during the festive period.

There are several potential triggers for marital strife, according to research by the government-funded Family Mediation Helpline. It could be the sheer cost of Christmas; being stuck at home too long; or having relatives you never liked anyway descending for what seems like endless days.

"Christmas is not a cause of divorce but it is certainly a catalyst, and January is the busiest time of the year for us as a result," said James Stewart, a partner at Manches, the country's biggest family law firm. "Families who don't spend much time together ordinarily are forced to spend a lot of time together. It is an expensive time and financial difficulties can exacerbate existing tensions."

Of course, most couples wouldn't want to do it in front of the kids. "There are many reasons why unhappy couples contemplating separating choose not to start proceedings in December. The main one is to give their families a happy Christmas. Once it is over and the children are back at school the decision has to be made whether the marriage can be repaired or not," Mr Stewart said.

That his firm's matrimonial team is twice as busy in January as in any other month is supported by research by InsideDivorce.com, an information website for couples. Forty-two per cent of separating couples cited infidelity as the main cause of their break-up. One third blamed emotional or physical abuse; 29 per cent boredom; and 22 per cent lack of sex.

Suzanne Kingston, head of the family law department at Dawsons Solicitors, said: "We are expecting this to be the busiest day and indeed week. A stressful Christmas can often be the final nail in the marital coffin."

Another group likely to be busy this week are accountants. The dire effects of debt will spill over into the laps of other agencies. Citizens Advice is braced for a busy day today; last year it handled 1.7 million debt inquiries, a 20 per cent increase on 2006.

Paul Farmer of Mind, the mental health charity, is fearful of the toll that debt and financial worries can take.

"As Britain's debt levels increase so will people's financial worries. For some this may lead to mental health problems such as anxiety, depression, self-harm and suicidal thoughts."

But there is a bright side to this dark January Monday. It is one of the busiest days of the year for booking holidays and hunting for new jobs.

Up to 500,000 people will book a foreign holiday, according to the Identity and Passport Service and the travel organisation ABTA.

Those not booking holidays or consulting divorce lawyers may well be trawling the internet for pastures new. A survey by Jobsite.co.uk showed that two out of five people planned to seek a new job in January, with most determined to start today.

Keith Potts, of Jobsite, said: "With time off over Christmas to reflect on your current job situation, it's perhaps unsurprising that the first Monday back in the office sends most people looking for something more fulfilling."

The most common reasons given for job-hunting are less stress, more satisfaction and, of course, more money. Christmas and the divorce lawyer have to be paid for somehow.

Don't all rush at once

406 people divorced each day in Britain in 2006

£13,000 was the average cost of getting divorced

13.8m British people visited Spain last year, 11 million visited France, 4.1 million the US and 3.4 million Italy

9 years is the average time a British worker spends in one job

Source: Times database, ONS, Norwich Union, Foreign Office.