Colleges are also suppressing evidence of abuse to stop commercial damage, a report on the survey, by the Further Education Development Agency, suggests. "In a competitive climate there are clear tensions for colleges in acknowledging drug-related problems."
The survey of all 489 colleges in England, Wales and Northern Ireland was carried out in the wake of the 1995 Government White Paper on drugs and parallel surveys by the Health Education Authority.
It suggests that campus problems are less significant than in the wider community. But it still reveals a disturbing problem which is not being adequately tackled, either because of a lack of funds or because the vulnerable groups are inadequately targeted.
College refectories were singled out as the areas most commonly used by dealers and pushers. The report says that franchising contracts to outside caterers and security teams may make things worse because staff are unfamiliar with students and the college ethos.
Most colleges are developing policies on drug abuse, education and prevention but key groups such as governors and part-time students are too often left out.
"Most colleges regret that recurrent FEFC funding arrangements could not readily accommodate whole-college initiatives on drug use and health promotions," says the report by Carole Mitchell, a Lancashire-based educational psychologist, and Mike Bone, a FEDA officer.
Links with police and drugs squads were common but not problem-free. "There are many concerns about inconsistency in police attitudes to drug use and users. Some colleges referred to 'trade-offs' with police, and undercover operations by drug squads."
Many other colleges have involved them in drug awareness training for staff and students. But the report also reveals a lack of college contacts with other colleges, schools, the youth service and social services. Only one in four had links with colleges and one in five with schools.
Around one in five colleges said the problems they had to tackle "frequently or very frequently" were drug use, drug-pushing, behaviour, security and unreasonable demands.
The Government White Paper identified FE as contributing to prevention, counselling and support services for students. The FEDA report shows that many have devised rigorous policies to tackle the problems. Many of these are included in the report.
But in an in-depth study of 30 sample colleges, one in 10 had no policy. Eight were only now formulating policies, two years after Government exhortations.
Where policies have been pursued, the fightback has been effective, Stephen Crowne, chief executive of the FEDA, insists. "The problem of drug abuse among young people cannot be avoided by colleges. As educators, they have a particular responsibility to guide students thorough the maze of issues that surround drugs."
The most commonly used drug was cannabis, though many colleges said Ecstasy was in use.
Several colleges said students used hallucinogens to enhance their artwork. A few said staff used drugs to relieve stress.
An HEA survey shows that a third of 14-year-olds have tried drugs, as have half of all 16-year-olds, suggesting that people are beginning to experiment with drugs at a younger age than in the 1970s and 1980s.
Barnsley College, one of several singled out for good practice, has strong links with all outside agencies and has appointed a counsellor to specialise in drug problems.
Kate Atkinson, head of student support, said: "Our strong links with external agencies helped to inform us that we can expect more experienced drug-users coming into college. It is not enough to offer preventative education alone. "