Can an employer treat fixed-term employees less favourably than it treats permanent employees?

Not unless this treatment can be justified objectively. The Fixed-term Employees (Prevention of Less Favourable Treatment) Regulations 2002 (SI 2002/2034) state that fixed-term employees must not be treated less favourably, on grounds of their fixed-term status, than comparable permanent employees, with regard to the terms of their contract or by being subjected to any detriment by any act or failure to act of their employer. This includes, in particular, rights in relation to periods of qualifying service and the opportunity to receive training or secure any permanent position within the company. If, for example, a permanent employee receives an increase in holiday entitlement after a certain amount of service, a fixed-term employee should also receive this increase after the same qualifying period. In order to ensure that fixed-term employees are not treated less favourably with regard to securing a permanent position, employers must ensure that they are informed of any available vacancies.