Forget quitting smoking. Forget losing weight. This year, a vast number of Britons at the dawn of the millennium resolved to lose something else — their spouses.

They’re calling it “clean slate syndrome.”

Divorce lawyers in particular — but marriage counselors as well — say that they’ve been inundated with calls from disenchanted spouses since New Year’s Day. These callers see the new millennium as the perfect time to either question, or to end, their not-quite-so-perfect relationships.

Celebrity couples, too, greeted the New Year by kissing their spouses goodbye. The former Spice Girl Melanie Brown, better known as Scary Spice, announced that her marriage to the Dutch dancer Jimmy Gulzar was ending — 15 months after they took their vows. (In the United States, Ted Turner and Jane Fonda announced their separation on CNN’s Web site this month following eight years of marriage.)

Vanessa Lloyd Platts, of matrimonial law specialists Lloyd Platts & Co., calls it “matrimonial millennium madness.”

“We have a flu epidemic in Britain, but we also have a [divorce] epidemic. If people continue to call us as they are now, there won’t be anyone left to get a divorce in 10 years,” she said.

Since New Year’s Day, her firm has received more calls than ever before — a volume so daunting that it’s been forced to turn clients away. Counseling agencies, too, have reported a flood of calls from disillusioned spouses eager to leave their mates — and supposedly all their troubles — behind.

Counselors at Britain’s largest relationship help line, the Samaritans, said they were so swamped with calls between Christmas and New Year’s that they beat last year’s record of 124,000 calls during the same period. Many of this year’s callers indicated that they had planned to get divorced once the holidays were over.

The consensus among counselors was that many couples put too much pressure on themselves to have a fantastically good time together on New Year’s Eve. They built New Year’s Eve up to be a night of revelry, unrivaled romance and — the piece de resistance — unbelievably great sex. But lots of couples woke up with a severe relationship hangover. Nothing had been as good as it was supposed to have been.

“Couples woke up and started to wonder whether their relationship was really a solid one,” said Judy Cunnington, director of London Marriage Guidance. “Then they started to wonder whether they wanted to spend another year like the last one.”

Symptoms of clean slate syndrome have been spotted in at least some parts of the United States as well.

“I couldn’t get anything done this past week because people constantly have been calling or e-mailing me. These are all people who are upset that their husband or wife has just left them. They don’t know what to do about it,” said Diane Sollee, founder of the Washington-based Coalition for Marriage, Family and Couples Education, who says that she normally receives only one or two calls a month from abandoned spouses.

Certainly, the number of marriages and divorces in any given country are prone to fluctuate with the seasons and the social tides. But marriage advocates argue that Britons’ sudden keen interest in divorce is particularly alarming since it comes on the heels of a long-term decline in the number of weddings here. At the same time, divorces have been creeping upwards: Last year, an estimated 167,000 couples divorced in Britain, compared with 155,332 in 1994. More people divorce each year in Britain than in any other country in Europe except Belgium.

All this has been reason enough for church leaders to predict — for the umpteenth time — the imminent demise of the nuclear family in Britain.

Meanwhile, the marriage experts are left scrambling for an explanation as to why so many Britons seem to be so eager to resolve their marital problems with divorce.

To explain the millennial madness, some experts speculate that people had given their partners an ultimatum: Shape up by Jan. 1, or this marriage is over. When their spouses didn’t reform, they dumped them.

Others argue that the divorce wave is a knee-jerk reaction to family problems over the holidays, a time of year that’s known for draining one’s emotions and finances.

“Many couples wanted to hang on for the holidays — especially because they were such a big deal this year — for the sake of the children,” said Andrew Price, a divorce lawyer in Paignton, south of London, who’s also noticed an increase in calls to his office this month. “All those days of forced frivolity really got to lots of people and so they were more than ready to seek a divorce once January arrived.”

But in the end, experts place most of the blame at the feet of the media, who, they say, raised couples’ expectations for the new millennium to unrealistic levels.

“A lot of people expected New Year’s Eve to be the best night of their lives. When it wasn’t, they blamed their partners and decided to start over again,” said Lucy Selleck, a counselor with Relate, Britain’s largest counseling agency for couples with 100 offices across the country.

Many of those offices have seen a rise in calls since Jan. 1. The office in Portsmouth, for example, took 57 calls on the first day of the year — more than twice the number recorded last year.

“People’s gut reaction is always to get rid of what they don’t like, but really we think people should work on their relationships and not go straight for a divorce,” Selleck said.

Meanwhile, church leaders say that they’ve been disappointed to see that Britons continue to be obsessed with Ferris wheels and the Millennium Dome, while they seem hesitant to engage in a discussion of serious issues — such as the collapse of the stable family in Britain.

Consider the statistics: There were 279,000 weddings in 1996, compared with 348,000 a decade earlier — a 20 percent decline. The most dramatic fall — 27 percent — was among couples marrying for the first time, down to 161,000 from 220,000 in 1986.

The declining marriage rate can be attributed, in part, to more couples choosing to live together outside of marriage. The government predicts the number of unmarried cohabiting couples — now about 1.5 million — will nearly double over the next 25 years.

At the same time, the number of divorces — which had fallen since peaking at 165,018 in 1993 — is back on the rise. Two in five marriages are now expected to end in divorce, although the rate is projected to climb to one in two by year’s end.

“Family breakdown is to our social ecology what global warming is to our natural ecology,” said Dr. Jonathan Sacks, the Chief Rabbi of the United Kingdom and Commonwealth.

The church has greeted the rise in divorce rates with new programs to promote family life. Some of their tactics have been decidedly quirky — such as conducting marriage and parenting courses for men in pubs. (They presume that the pub provides a more comfortable atmosphere than, say, a church hall.)

The church also has urged the British government to cut taxes for families, to give couples a financial incentive to get — and stay — married. Currently, those couples who live together have little to gain financially by getting hitched.

Ironically, the millennium seems to have had a very different effect on the marriage rate in other European countries. In France, for example, the institution of marriage is more popular now than at any time since the 1970s with 400,000 weddings expected there this year — compared with 280,000 in 1999. And, although France already has one of the lowest rates of divorce in Europe — almost half that of England — the number of divorces is falling for the first time in 10 years.

But back in the United States, Sollee predicts the year 2000 will not only be a boom time for divorces, but, eventually, for weddings as well.

“A lot of people who have been living together for 10 years think it could be jazzy to get married in the year 2000,” she said.

But will it be enough to reverse the long-term trends? Probably not.

In Britain, Vanessa Lloyd Platts may have summed up the modern relationship best when she said: “Some people wanted to rush out and get divorced before the millennium. And, obviously, lots of people have decided to get divorced now that the millennium is here. People these days are always looking for an excuse to get out of a relationship and to search for something better.”

Dr. Penelope Leach, child-rearing guru and advocate of unlimited affection for children, appears ready to administer a spanking. The British psychologist and author of the parental advice bible “Your Baby and Child” will not, however, be putting any kiddies over her knee. Instead, her sights are set on American Gary Ezzo, an evangelical Christian minister and competing child-care expert who, with his wife, Anne Marie, advocates a “tough love” approach to child-raising. That approach includes spanking as well as scheduled feedings, scheduled potty training and a rule that infants be left to cry themselves to sleep at the age of 8 weeks.