The NHS in Scotland faces a massive backdated holiday pay bill from nurses who say they have been discriminated against under the European Union law.

The Royal College of Nursing in Scotland is threatening to take the Scottish Executive to an industrial tribunal in a bid to bring holiday pay in line with colleagues across the rest of the UK.

RCN Scottish board secretary James Kennedy told a conference in Ayr last week that Scottish nurses face discrimination compared to colleagues in England and Wales where holiday pay includes payments for working nights and weekends.

He said that under the terms of the EU working time directive, which dates back to 1998, nurses on annual leave should receive the same pay as during the rest of the year. But he said that in Scotland, nurses, whose normal salary includes payments for working nights and weekends, find their pay reduced to a basic salary while they are on holiday.

'The current system in Scotland is blatantly unfair and means nurses who are working under tremendous pressure are, in effect, financially penalised for taking annual leave.

'Everyone agrees that a strong, motivated nursing workforce is vital for the modernisation of the health service in Scotland, but we won't achieve this until nurses feel valued and treated justly.'

Mr Kennedy said the RCN was looking for a retrospective deal dating back to 1998.

'We would have to get figures for all our members as to what they are owed but it would be a sizeable amount, 'Mr Kennedy told HSJ .

He cited an example of a nurse in Glasgow, who works four nights a week and takes home about£366 a week.

But when she is on leave, her weekly pay is cut by£80.

A spokeswoman for the Scottish Executive said: 'We are aware that there are anomalies in the system and we are committed to a level playing field for Scottish nurses alongside their counterparts throughout the rest of the UK. We are looking closely at the legal details right now and expect clarification to be produced very soon.'