More than a third of colleges are deeply concerned about drug problems on campus, new research shows.
The findings reveal colleges are facing a catalogue of drugs-related issues, including dealing on their premises and disruptive behaviour among student users.
Some report cannabis joints being rolled in toilets, and one college even admitted that part of its refectory had been turned into a "no-go zone" by pushers.
The survey, carried out by the Further Education Development Agency (FEDA), reveals larger colleges - tertiary and FE institutions - are more likely than smaller specialist or sixth-form colleges to experience serious drugs problems.
Out of 260 colleges responding - well over half the sector - around 100 felt the issue was either significant or very significant on campus. Student drug-taking led to poor study performance, absenteeism or even dropping out, damaging colleges' retention rates.
Though many stressed that those dealing in drugs were usually only a small group of students or were from outside the college, they said the trade caused security problems and disruption on campus. Pressure was increasing in some colleges to restrict access to sites. Campus thefts and break-ins were often by outsiders seeking to fund a drugs habit.
Younger students, aged 16-19, and those in full-time study were likeliest to be involved in drugs misuse, but there were a few reports of staff involvement.
Many colleges found alcohol was an even greater concern than drugs, with one college revealing problems linked to drinking included "tiredness, poor concentration and dehydration, especially on Monday mornings". Several had set up campus branches of Alcoholics Anonymous.
Colleges also report concern over drugs in their local community. Over two-thirds thought they were a significant or very significant issue.
FEDA launched its research project in response to the Government White Paper Tackling Drugs Together, which set out a co-ordinated three-year action plan and indicated that FE would need to consider its contribution to prevention, counselling and support services for students.
The survey revealed that, while some colleges were forging ahead with tackling the issues, others were less able to recognise and confront their problems. Many were conscious that drugs problems could damage their image. FEDA aims to identify examples of good practice and provide guidance to colleges throughout the sector.
Anne-Marie Warrender, of the FEDA project team, said colleges were becoming increasingly aware of drug dealing and occasional use on their premises. "There have been a number of instances of problems and disruptive behaviour by students in classrooms which staff have attributed to the effects of drugs, though it is very difficult to pinpoint."
Colleges were increasingly developing drugs awareness programmes, either attached to the tutorial systems already in place or devised with the help of outside agencies.
Most were opting for a low-key, informative rather than punitive approach, said Ms Warrender. "They are very conscious of the need to raise awareness of both staff and students of the issue."
Dave Stott, head of student services at Suffolk College, where students are creating their own drugs education materials as part of a major information initiative, said many colleges were "desperately anxious" to find a way of tackling the issue. "There is a lot of fear in colleges of the problem simply appearing in local press as shock-horror headlines."
Barnsley College, another of 30 colleges identified in the FEDA survey as leading the field in tackling drugs problems, has opted to integrate support within its existing counselling system.
Kate Atkinson, head of student support, said: "Our approach is to make sure people have enough information so that they know exactly where to find advice and support and can make informed decisions. We expect students to come with a work ethic and try to support them."