RMT member and conductor Chris Rodway won his original case at the Employment Tribunal after being disciplined by Southern Trains in July 2003 for taking a day off to look after his son so that the child's mother could visit her disabled sister.

Chris had submitted a written request for a day's parental leave on July 5, 2003, after the company told his that his earlier application for a day's annual leave might be granted, but might not.

It was only two days before he needed to take leave that the company told Chris that parental leave would not be granted. After trying and failing to see his manager, Chris took the day off but was handed a written warning and had a day's pay deducted.

Chris turned to the Employment Tribunal, which ruled in his favour, noting that the purpose of the European Directive that gave rise to the Maternity and Parental Leave Regulations 1999 was to allow for 'better organisation of working hours and greater flexibility', and to allow for the 'reconciliation of work and family life'.

The Tribunal said parents should be allowed flexibility to take parental leave, and found that interpreting the Regulations to mean that parental leave had to be taken in blocks of at least a week substantially undermined the purpose of the Directive.

The Tribunal also concluded that being forced to apply for a week's unpaid leave would act as a powerful disincentive to a parent who only wanted to take one day's unpaid leave. Chris was awarded £750.

However, Southern appealed and the ruling was overturned by the Employment Appeals Tribunal, which decided that the minimum period of parental leave was one week and that Chris's application was therefore not covered by the Regulations.

"It is clear that the law now needs to be changed to reflect the needs of parents in the 21st century," RMT general secretary Bob Crow said.

"What is the point of only allowing parental leave to be taken in minimum blocks of a week, especially when it is unpaid anyway? This ruling is an injustice for our members - but inflexibility like this can't be good for employers either.

"How can our members strike a work-life balance if responsible parents are deterred from applying for parental leave?

"RMT will continue to campaign so that parental leave can be taken in periods of less than a week," Bob Crow said.

"All I wanted was a day off to look after my son Ryan - little did I know it would end up in the Court of Appeal nearly two years later, but for me this is a point of principle," Chris Rodway said.

"The Employment Tribunal in the first instance applied a purposive approach to the Regulations in keeping with the spirit of the law, but the Court of Appeal stuck rigidly to the letter of a law which does not work in practice and needs to be reviewed," said solicitor Doreen Reeves of Edwards Duthie.