British women have a greater tendency than men to go off the boil after a year with the same partner, new research suggests.

Women in relationships lasting more than a year were around four times more likely to show a lack of interest in sex than those in shorter relationships, scientists found.

But the same trend was not seen in men, for whom there was no statistical difference between self-reported lack of sexual interest among those in longer or shorter lasting relationships.

The surprise finding comes from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), the largest study of sexual habits in the UK.

A similar association was seen between women whose general interests differed from those of their partners and lack of sex drive.

Researchers carrying out the survey interviewed 6,669 women and 4,839 men aged between 16 and 74 who reported having at least one sexual partner in the past year.

Overall, roughly a third of women (34%) said they lacked interest in sex, compared with 15% of men, the study published in the journal BMJ Open found.

Men and women had broadly similar rates of not feeling emotionally close to their partners during sex, or to have experienced their partner having sexual difficulties. Women were slightly more likely to find it easy to talk about sex than men.

Both men and women were at risk of being put off sex by past experiences of forced sex, poor mental and physical health, and recent sexually transmitted infections (STIs).

In women only, low interest in sex was linked to having three or more partners in the past year, having children under five in the household, and not sharing a partner’s sexual preferences.

Lead researcher Professor Cynthia Graham, from the Centre for Sexual Health Research at the University of Southampton, said: “Our findings show us the importance of the relational context in understanding low sexual interest in both men and women.

“For women in particular, the quality and length of relationship and communication with their partners are important in their experience of sexual interest.

“It highlights the need to assess and - if necessary - treat sexual interest problems in a holistic and relationship, as well as gender-specific, way.”