Education Secretary Charles Clarke voiced support last week for schools which had reinstated traditional uniforms. He said that they helped give schools a sense of identity and “clearly have a marked effect on improving behaviour and standards”.

His announcement followed similar comments by the chief schools inspector, David Bell.

Mr Bell told independent school heads last month that uniforms, along with school councils and prefects, were “symbols of belonging” that helped to improve standards.

Parents appear to support these claims. A survey by the Department for Education and Skills showed that 83 per cent of parents favoured uniforms and the majority felt they were well-priced and contributed to good behaviour and better school standards.

But 227 school pupils were also questioned as part of the same survey. The majority opposed uniforms, saying they had no impact on behaviour or standards and were too costly.

The Office for Standards in Education and the DfES say that anecdotal evidence is available to show the link between uniforms and improvement, and the DfES has produced a small list of schools to back up the case.

However, examples can also be easily found of schools which have succeeded without uniforms. In east London, Tower Hamlets education authority has been praised for having the most improved primary schools for three years running, yet only five of its 102 schools have uniforms.

The academic evidence both in the UK and America also appears inconclusive.

An analysis of American national test results in 1997, led by sociologist Dr David Brunsma, from the University of Alabama, concluded that school uniforms had “no direct effect on substance use, behavioural problems, or attendance”.