School uniforms should be made VAT-free to bring down their "rip-off" prices and boost social mobility, ministers will be urged this week.

Frank Field, the independent MP, said ministers should end the school uniform “rip- off” and lift VAT from 13-14 year olds to 18 year olds for school clothes would help social mobility and poorer families.

Some families have to spend hundreds of pounds on new uniforms every September.

Mr Field will raise his concerns in a debate when MPs return to work in the House of Commons tomorrow.

Mr Field will set out how parents are often forced to spend between £250 and £300 on school PE kit and sports equipment, shoes, trainers as well as shirts/blouses, skirts/trousers, ties, jumpers, shoes, socks, tights, blazer and coat.

Some parents are forced to ask the children’s grandparents for help with the costs of uniform.

Clothing and shoes for young children have been charged a zero rate of VAT since the introduction of the tax on 1 April 1973.

The problem is that there is no definition of the term "young children" in VAT law.

Instead, the VAT relief is based on the maximum size an average child will be on their 14th birthday.