Under health and safety law, colleges must carry out an assessment to gauge the measures required to ensure the safety of employees and members of the public, including students.
Fred Sherwood, the health and safety director for the Association of Colleges, says that colleges spending the most on security are the ones that realise how far people and property are at risk.
"It's interesting that some have decided to spend a fortune, while others have not," he says.
Colleges in inner cities often express the most concern about personal safety, as well as protecting IT equipment and other expensive equipment. Agricultural colleges in rural areas are likely to be more worried about theft than violence against staff or students.
Sherwood, along with Steve Hirst from West Thames College, represents the association on the Health and Safety Commission's education advisory committee. Its 1997 report on violence in theeducation sector recommended that institutions look at measures such as restricting access to school or college grounds, entry control or surveillance systems and panic buttons or personal alarms for staff working in outlying buildings.
High-level perimeter fencing was another idea, but Sherwood warns colleges to be careful. Intruders who injure themselves on college premises could prosecute the college, if the college could be shown to have been negligent in the way it erected, say, a barbed wire fence.
"Although you have to keep people out, you can't injure them in the process," he says.
Steve Craig, health and safety support officer for Natfhe, the lecturers' union, says colleges are generally better at securing their property than protecting people. But he maintains that CCTV be used for security and not to check on classrooms. "It must be transparent and not used for monitoring purposes," he says.