Ms Allonby was employed in the office technology team of Accrington and Rossendale College from 1990 until 1996 when all 341 part-time staff at the Lancashire college were made redundant and the agency Education Lecturing Services (ELS) were contracted to provide lecturers.

Ms Allonby’s union-backed action against the college, ELS and the Department for Education and Employment - claiming unfair dismissal and sexual discrimination against the college, equal pay and rights with college employees and access to the Teachers’ Superannuation Scheme - failed on all counts.

The tribunal found that there was prima facie discrimination against women in the introduction of ELS but said that the college’s decision to use the agency was justified. It also ruled that Ms Allonby was unfairly dismissed but decided not to award any compensation.

ELS, which has some 40,000 lecturers on its books and supplies staff to around a quarter of all colleges, hailed the decision as “an excellent result”. The agency’s managing director Frank Lord said: “Colleges currently using traditional casual arrangements for employing part-time staff now face a clear choice. In order to comply with employment legislation there are really two alternatives: fully fractionalised contracts for all part time staff or third party provision of lecturing services.”

NATFHE has lodged an appeal against the ruling and has vowed to pursue the case for equal rights for agency staff to the European Court of Justice. The union’s general secretary Paul Mackney said: “Although we are disappointed at the ruling, we are optimistic for the future. We are looking to Europe and the government’s Fairness at Work legislation to make some headway on giving contract workers the same rights as employees. ”