Companies need to be very careful in the work that they offer women returning from maternity leave, according to employment experts at MFG Solicitors.

Partner Sally Morris, head of the employment team, noted that under the Maternity and Parental Leave Regulations 1999, an employee who takes additional maternity leave is entitled to return to "the job in which she was employed before her absence or, if it is not reasonably practicable for the employer to permit her to return to that job, to another job which is both suitable for her and appropriate for her to do in the circumstances".

Her warning follows the ruling in Blundell v Stockton on Tees Borough Council, a case under the sex discrimination rules affecting pregnancy where a teacher had claimed she was not offered exactly the same job she was carrying out before she went on maternity leave.

Miss Morris said: "She lost the claim and took it to the Employment Appeal Tribunal which has now ruled for the first time on what criteria should be used when determining what counts as the same job under the regulations."

Both tribunals rejected her claim, saying that the position she had held as a reception class teacher was temporary as teachers were often moved from one role to another over a period of time to give them broader experience. Miss Morris said: "The decision was that the precise post she had occupied immediately before taking maternity leave was temporary, and in effect she was a teacher employed to teach."

The tribunal decided that it was "not obliged to freeze time at the precise moment the occupant takes maternity leave, but may have regard to the normal range within which variation has previously occurred".

Miss Morris said: "It is important to make the job descriptions as flexible as possible."