The Association of Colleges said staff with four years’ service would be given permanent contracts when they were renewed, unless employers can show “objective reasons” to refuse.

Evan Williams, the association’s employment policy manager, said: “Colleges are ready, or they should be. A lot of colleges have been looking at this for a number of years.

“The number of fixed-term contracts has been falling for the past few years. I think a permanent contract is easier for colleges to manage once you’ve got them up and running.”

But the AoC did not know how much the changes would cost its members, although colleges which have already been through the process reported significant costs.

Tower Hamlets College began reducing its dependence on temporary staff six years ago.

In 2000, it began a three-year programme to put part-timers, who mostly taught basic skills or creative arts, on to permanent contracts, arguing that casual working was undermining their efforts to improve literacy and numeracy.

At the time, the college said it would cost pound;100,000 to give 300 hourly-paid lecturers rights and benefits equivalent to their permanent colleagues.

“Every college is different,” Mr Williams said.