A survey of nearly 1,500 young people in London found that 70 per cent of 15 to 16-year-olds expected to gain five or more passes at A*- C, yet the average pass rate was only 30 per cent.

In one school, 80 per cent of 15-year-olds said they expected to gain five or more of the top grades, but only 11 per cent actually achieved these results this August. In another, 95 per cent of students expected to achieve top grades but only 34 per cent did so.

The study was carried out by Dr Jane Hemsley-Brown and professor Nick Foskett, both from the research and graduate school of education at the University of Southampton. Their paper was presented to the British Educational Research Association’s annual conference last week at the University of Leeds.

Asian students were the most ambitious - 77.5 per cent or more predicted achieving the top grades, compared to 60 per cent of white students.

The students surveyed were also ambitious for the future. Some 41 per cent hoped to take a degree, and only 2.8 per cent said they were not interested in studying further.

There were striking differences between career choices when comparing ethnic groups. Asian young people were in the majority in fields such as finance and computing, law, medicine and scienceengineering.

Black students were well represented in finance and IT jobs. Asian students were less likely to have chosen a career in the arts and were under-represented in theatre or TV and film. White students showed themselves to be more interested than others in art and design and media courses.

A third of Asian fathers were working in hospitality, but no Asian young people had chosen a career in this field.