A third of British children who leave school with poor qualifications expect to "end up on benefits", new research has shown.
The Prince's Trust also found around one in five have "abandoned their ambitions" due to a lack of success at school, while those with fewer than five GCSEs are almost twice as likely as their peers to believe that they will "never amount to anything".
The survey of people aged 16-25 has prompted the trust to call for more vocational support for those leaving school with few qualifications, to help them into jobs.
Last year, two-fifths of young people across England did not achieve five GCSEs graded A*-C, including English and maths.
Martina Milburn, chief executive of the youth charity, said: "Thousands of young people's ambitions are crushed by exam results each year.
"Many of these young people have faced problems at home or bullying at school, so their exam results don't reflect their true potential.
"It is now more important than ever to invest in vocational support and training for young people who are not academically successful.
"Government, employers and charities must work together to get them into jobs. Without this, thousands will struggle to compete, leaving them hopeless and jobless."
The Prince's Trust says three-quarters of young people who enroll on its intensive training schemes for struggling school leavers move into work, education or training.
More than 2,000 people were questioned as part of the online survey, which also showed one in 10 young people believe their exam results will "always" hold them back. This increases to a quarter (26%) among those who left school with poor grades.
Last month David Cameron hailed a "rigorous, engaging and tough" new national curriculum, which he said was critical to Britain's future economic success.
The Prime Minister described the changes, due to be introduced in September 2014, as a ''revolution in education''.