Fewer young people are gaining work experience while they are in full-time education, according to a new study.
The Institute for Public Policy Research (IPPR) think-tank said that half of all unemployed young people who are not in education have never had a job.
The study, published ahead of the latest unemployment figures, also showed that three quarters of young people in all levels of education do not have a job.
The analysis of official figures revealed that since 1998 the number of 16 to 24-year-olds who have never had a job has almost doubled to 640,000.
Spencer Thompson, economic analyst at the IPPR, said: "Gaining experience of the world of work while studying is vital for the future job chances of young people, but fewer and fewer young people are working while learning.
"These findings show the need for a job guarantee for young people, paid at least the minimum wage, to provide them vital with experience of the workplace. By having job experience on their CV when they leave full time education, young people will be at an instant and much needed advantage when entering the jobs market.
"This guarantee would also ensure that those who cannot afford to participate in unpaid work experience placements are not at a disadvantage when it comes to competing for jobs. Despite it being illegal to not pay young people a minimum wage, the prevailing culture of unpaid internships in the private sector is a major problem that needs to be challenged."
A separate study by jobs website Monster.co.uk suggested that employers were damaging their reputation by bad recruitment practices.
A survey of 5,300 jobseekers revealed that four out of five had a negative view of a company because of the job application process.
Most complained that they did not receive a response to their application or any constructive feedback.
Sinead Bunting, head of marketing at Monster.co.uk, said: "It is worrying that so many employers still don't realise the potential impact of a poor recruitment process on their brand. Jobseekers are also consumers and by failing to respond, acknowledge or engage with them, employers could be losing out on valuable custom.
"Many companies are inundated with CVs but with the technology available today, it should be possible to ensure all applicants at least receive a friendly response."