According to research from the London School of Economics, 18 per cent of youngsters fall into this group, in contrast to official figures that put the figure at seven per cent.

Derbyshire Chamber chief executive George Cowcher said: "The underlying causes may be not be straightforward but we have arrived at a situation where a sizeable proportion of our children have no idea of how they are going to earn their way in the world and no motivation to find out.

"The Government's green paper on welfare reform may be the opportunity to galvanise them into trying new things, and at least finding out what they're suited to. We must seize this opportunity for genuine reform while making a commitment to improve the skills of those looking for work."

Official figures on NEET teenagers take into account all work or training undertaken by young people over several weeks, but the LSE research is based on what teenagers spend most of their time doing.

Under the Government's plan for a shake up of the benefits system, claimants will have to carry out four weeks' community work once they have been unemployed for more than a year. After two years, they will be ordered to work full-time.

Mr Cowcher said: "With increased pressure on the economy, taxpayers cannot be expected to support those who do not work out of choice. Those unemployed young people who are not in education or training are selling out their futures."

* Employers have cautioned the Government against damaging the quality of apprenticeships in its desire to ensure every suitable school leaver has the right to work as an apprentice.

Over the last ten years the Government has more than doubled the number of young people and adults starting high-quality apprenticeships, but skills secretary John Denham has said that in five years he wants every school leaver who has achieved basic maths and English skills to have the right to an apprenticeship.

Derbyshire Chamber chief executive George Cowcher said: "Apprenticeships are an essential part of creating the highly skilled and capable workforce our economy demands, and Mr Denham's proposals will have the backing of the business community who all too often struggle to recruit suitable and willing employees.

"However, if this is to be a success, the Government must ensure all firms are engaged and supported when providing apprenticeships. Crucially, the apprenticeship brand must not be weakened in order for the Government to achieve its commitments. Work based learning must come first in any apprenticeship programme."