Figures also showed they spend three times as much on entertainment, and twice as much on clothes, as on their studies.

The statistics are the result of a survey of 1,000 students at 10 universities in England, Wales and Scotland carried out by MORI for the right-wing think-tank Adam Smith Institute.

It asked them about their sexual, drinking and socialising habits, as well as how much they spent on study, and what they wanted from future jobs.

Findings vary between colleges

The findings showed that as well as nearly 30% claiming to have regular sex, more than half of students have used illegal drugs in the past year.

However 61% of all students questioned said they had never used illegal drugs, and a fifth of students said they had not had sex in the past year.

Some of the findings varied greatly between universities. Manchester University emerged as having the highest proportion of students who used drugs and had frequent sex.

Only 31% of Manchester University students said they had never used illegal drugs, with 4% admitting to using them every day, and 16% at least once a week.

A total of 40% said they had sex at least once a week, and one in 11 stated they had sex every day - a figure equalled by students at Cambridge University.

Career choice

Manchester students also spent the most on alcohol - �25.39 per week, compared with an average of �20.32.

On the more abstemious end of the scale, South Bank University emerged as the most drug-free, with 77% of students saying they had never used illegal drugs. Only 3% of South Bank students said they had sex every day - the same figure as at the University of Central England in Birmingham.

Pulling power: Drink remains a high priority

The survey also found that the biggest influence on students' career choice was the prospect of working with sociable and friendly colleagues (58%), followed by a high salary (48%).

More than three-quarters said the top ingredient for success was determination and ambition, while 74% said it was also educational qualifications.

But a spokesman for the National Union of Students (NUS) said the survey had "no context", and the findings were not representative of all students.

'Irresponsible comparison'

He said NUS estimated figures, calculated on spending per year rather than per week, suggested the gap between student spending on alcohol and books was much narrower.

Outside London, students spent an average of �774 a year on leisure, compared with �454 on books and equipment. The leisure figure for London students was higher at �929.

"There is no such thing as an average student, and this is an irresponsible comparison, " he said.

"What does the survey tell us? Is it that students aren't spending enough on books, that they're spending too much on alcohol, or that alcohol is more expensive than books?

"Our figures show that students spend 60% of their income on accommodation, and that 40% of them work during term-time to find enough money to live. If they then spent that money on alcohol, that's up to them.