The number of young long-term jobless in Britain has almost doubled in the last two years according to new analysis of official unemployment figures.

The research conducted by the Royal Bank of Scotland and the Prince's Trust charity suggests the cost of youth unemployment could be as high as £155m a week.

While the latest government statistics show falls in unemployment and a shorter dole queue, today's analysis of the data suggests the headlines disguise the plight of jobless young people.

The number of 16-24-year-olds out of work for more than 12 months has almost doubled in two years to 232,000 - a 16-year high. The number claiming Job Seekers Allowance for over a year has more than trebled in the same period.

The increase in long-term joblessness is a particular concern because evidence from previous recessions suggests that for young people taking the first tentative steps into the world of work, if unemployment lasts more than a few months it has a devastating impact on their life chances.

In East London, Laura Hurrell has been claiming Jobseekers Allowance for over a year. She tells a story of countless applications, a handful of interviews and daily knock-backs. Here she is, at the beginning of her working life, and it seems no-one wants her.

"It's been horrible. I am on depression tablets - I just don't want to be on benefits for the rest of my life." Laura lacks both self-confidence and skills. One in 10 16-24-year-olds in the UK left school without qualifications and it is this group who are suffering most in the downturn.

"Most of my friends have got jobs - they go out and they do stuff. But me, I don't because I just stay at home because I can't spend no money because I have to save it."

The Prince's Trust helps tens of thousands of young often disadvantaged young people every year. For as little as £1,000 investment, the charity has been able to turn many lives around.

Chief Executive Martina Milburn believes ministers ignore the implications of youth unemployment at their peril:

"For a relatively small amount of money you can help give young unemployed people confidence and the tools they need to get a job, otherwise it's too easy just to say we won't bother with them, we'll leave them, and then in 20 years time look at some huge great benefits bill and wonder how we got there."

Evidence of how fortunes can change is to be found among the gleaming towers of London's Dockland. Bankers out for a meal do not realise that the confident young woman making their burrito was rescued from worklessness and poverty by the Trust.

A few weeks ago Shoyagay Nelson was a single mum who could barely feed herself and her baby and so lacking in self-belief she"stared at the floor"all the time. She is now regarded as a high-flyer by the Wahaca restaurant chain having been given help to get on a chef's course.

"I feel really good because now I feel healthy, I can walk down the road with my head held high knowing that I have got a job and that I can provide for my son."

Government ministers say their Work Programme and welfare reforms are designed to ensure another generation does not get locked into benefit dependency but they accept the challenge is to get business moving again, creating jobs and giving young people the chance to get skills and experience.

Today's report estimates the price of failure. Adding together unemployment benefit and lost productivity the authors suggest the cost of youth joblessness currently runs at up to £155m every week. If we fail to support the hundreds of thousands of youngsters who have been without work for a year already, they suggest we risk betraying a generation.