Retail pay rates have climbed 3 per cent this year, lagging behind the average UK rise of 3.5 per cent.

However, the biggest retailers – especially grocers – have increased rates by an average of 3.7 per cent, researcher Incomes Data Services (IDS) reported.

In some instances staff on the lowest wages or national minimum wage – which rose to£5.73 an hour this year – received the highest awards.

IDS senior researcher Lois Wiggins said: “There is a broad contrast between the rates paid at the major supermarkets and other retailers, as the big supermarket chains are providing the largest pay gap with the national minimum wage.”

The number of starter or minimum rates paid at the national minimum wage level shot up from 33 per cent in 2007 to
53 per cent in 2008.

Established staff rates are rising faster than starter rates. Existing staff typically receive£5.97 an hour and the gap between this and the national minimum has increased from 3.3 per cent in 2007 to 4.2 per cent in 2008.

Wiggins said: “It may be that trained sales assistants are seen as better overall value than new, inexperienced staff and retailers would rather pay a higher wage to retain them.”

The IDS research also revealed that 46 per cent of retailers no longer pay Sunday overtime.