Scottish Labour MPs yesterday lobbied Gordon Brown to end the "morally unjustifiable" practice whereby tips which low-paid staff in bars and restaurants receive form part of their wages instead of being on top of them.

The back benchers are concerned that customers believe when they add a tip to a bill and pay by card or cheque, then it goes on top of the waiter's or waitress's wage when, in fact, it forms part of their payroll.

The best guarantee, they point out, is for customers to tip in cash.

Michael Connarty, the MP for Linlithgow and East Falkirk, who led the delegation of Scottish MPs to see the Prime Minister and who has been campaigning on the issue since 2003, made clear that workers - the majority of whom are almost certainly on the national minimum wage of £5.52 for those 22 and over or £4.60 for those aged 18 to 21 - should "get their tips on top of the minimum wage".

He added: "We have to get people to ensure they put cash on the table."

After the MPs' meeting with Mr Brown, Mr Connarty said that he "gave us a signal he would look seriously at it".