Men actually daydream about sex about 34.2 times a day, which works out as every 28 minutes - but that's still almost twice as often as women, who think about it every 51 minutes.

The latest research showed that women have erotic thoughts on average 18.6 times a day, which works out as once every 51 minutes, when allowing for eight hours sleep.

Psychologists at Ohio State University asked students aged 18-25 to record every time they thought about sex, food and sleep each day for a week.

The highest score for a woman was 140 sexual thoughts in a day - or once every seven minutes.

On average, women thought about food 15.3 times a day (once every 62 minutes) and sleep 13.4 times (every 72 minutes).

Men thought about food 25.1 times a day (every 38 minutes) and sleep (every 33 minutes).

Ultimately, the survey showed that men are more focused on all their physical needs than women - including sex.

However, it could be that woman under-reported their naughtier thoughts due to social pressure.

These findings are supported by a recent survey by Lovehoney.

The survey found that 59 per cent of men think about sex several times a day, compared to 45 per cent of women.

Lovehoney co-founder Neal Slateford said: 'The results show the importance of sex to all of us.

'It's great that men think about sex twice an hour and women once every 51 minutes. Obviously they are averages, so the figures are far higher for many people.

'Certainly that is our experience at Lovehoney - and it is proved by the results of our own survey.

'We are all developing a more relaxed and far better attitude towards sex in Britain.'