The secret to a happy and long lasting marriage, according to research experts at Bath University, is for men to choose a wife who is younger - and smarter - than them.

Ideally the female should be around five years younger, the study showed.

The research involved approximately 1,500 couples who were either married or in a serious relationship and was published in the European Journal of Operational Research.

Following up five years later on 1,000 of the couples the research found that when the women were older than the men the chances for divorce were three times higher than if they were the same age, the 'BBC News' reported.

Couples in which one partner had been through a divorce in the past were at more of a risk of breaking up than if both partners were divorcees.

The likelihood of long lasting marital bliss is a lot higher where the man is older than the woman and also if the woman is better educated than her partner.

Study leader Dr Emmanuel Fragniere and colleagues believe that when choosing a partner, people would be wise to take into account "objective factors" such as age, education and cultural origin.

"That would definitely help reduce divorce", the researchers said.