Divorce makes men - and particularly fathers - significantly richer. When a father separates from the mother of his children, according to new research, his available income increases by around one third. Women, in contrast, suffer severe financial penalties. Regardless of whether she has children, the average woman's income falls by more than a fifth and remains low for many years.

The research was carried out by Professor Stephen Jenkins, a director of the Institute for Social and Economic Research and chair of the Council of the International Association for Research on Income and Wealth.

His survey, Marital Splits and Income Changes over the Longer Term, is the first to track the changing wealth levels in Britain associated with a marriage breakdown. The findings have been welcomed by specialist family lawyers, including Resolution and Family Law in Partnership (Flip).

"The general belief that men get fleeced by their divorces while women get richer and live off the proceeds has long been due for exposure as a pernicious myth," said Ruth Smallacombe, a family consultant at Flip. "In reality, women often suffer economic hardship when they divorce. In addition, the resentment caused by unfair financial settlements has many knock-on effects, damaging ongoing relationships with former spouses and a woman's ability to move on with her life."

Jenkins's research found that the incomes of "separating husbands" rise "immediately and continuously" in the years following a marital split. "The differences between the sexes are stark," he said. "But this is not so much a gender thing as a parent thing. The key differences are not between men and women, but between fathers and mothers."

He found that, when a man leaves a childless marriage, his income immediately rises by 25%. Women, however, suffer a sharp fall in income. Their financial position rarely reaches pre-split levels.

Jenkins combined data from 14 different British Household Panel Surveys over 1991 to 2004 with the findings from five European surveys. Recalculating the results using the formula by which the government measures poverty, he established new per capita incomes. Jenkins found that the positive effect on men's finances is so significant that divorce can even lift them out of poverty, while women are far more likely to be plunged into destitution. Separated women have a poverty rate of 27% - almost three times that of their former husbands.

Maintenance paid by former partners also has little impact, said Jenkins, as just 31% of separated mothers receive payment from the father of their children.

"There are only two factors that have an impact on women's financial position, post relationship breakdown," said Jenkins. "The percentage change in income is less if they have worked beforehand and continue working afterwards. The impact is also reduced if they start working after the relationship breakdown. There is also a potential positive impact if she remarries," he added, "although the impact is a small one."

The position can be reversed if a separated man has more children with a new partner while paying maintenance to his first family. The only way to level the playing field is to make men and women more alike in terms of roles in the family and in the labour market. "Until these fundamental issues change, these realities will remain essentially unchanged," he said.

Professor John Ermisch, author of An Economic Analysis of the Family and Lone Parenthood: An Economic Analysis, agreed that women are disproportionately penalised following relationship breakdowns, but said that the margin of unfairness is gradually reducing.

"Employment transition rates reveal that the proportion of women with dependent children who stop working after a marital split has almost halved between the late 1990s and early 2000s, from 16% to 9%," he said.

According to Labour Force Survey data, the proportion of all separating wives in paid work has increased over the 1990s from around 66% in 1993 to 74% in 2002. The proportion of separating women with children who have remained in work has increased from 41% to 58% over the same period, increasing this group's employment rate by 16%.

"The most likely explanations of these trends are increases in women's attachment to paid work, and increases in government rewards to paid work relative to not working, both of which are associated with the various changes in the late 1990s to the system of in-work support," said Ermisch.

Case study: 'I try not to be too bitter'

Elouise and her husband had been married for 20 years when they divorced 18 months ago. They have three children, aged 11 years, 3 years and 18 months old.

"My husband told me we would split everything down the middle. I got a huge shock when I realised he had hired a crack legal team who managed to hide a large proportion of his assets and write off most of his income. I didn't stand a chance. On paper I got 50% of everything. In reality, however, he walked off with enough money to buy a house in town outright and a new car, while also taking the kids on a couple of foreign holidays each year.

"I fight a constant battle not to let myself become overwhelmed with feelings of anger over the differences in our lives. I find it almost unbearable that I have to scrimp and save to bring up the kids, while his lifestyle is noticeably more comfortable and extravagant than when we were together."

Parting by numbers

• Almost half of all marriages in England and Wales will end in divorce.

• At least one child under 16 is affected in 53% of all cases, with nearly two-thirds of them being under 11.

• Since 1997 average age of divorce has risen from 40.2 to 43.7 years for men and from 37.7 to 41.2 years for women, partly due to the rise in age at marriage.

• The highest rate of divorce is among men and women in their late twenties.

Source: www.statistics.gov.uk