I giovani sono diventati più scemi in una generazione. In Inghilterra, naturalmente.

Bright teenagers are a disappearing breed, an alarming new study has revealed.

The intellectual ability of the country's cleverest youngsters has declined radically, almost certainly due to the rise of TV and computer games and over-testing in schools.

The 'high-level thinking' skills of 14-year-olds are now on a par with those of 12-year-olds in 1976.

The findings contradict national results which have shown a growth in top grades in SATs at 14, GCSEs and A-levels.

But Michael Shayer, the professor of applied psychology who led the study, believes that is the result of exam standards 'edging down'.

His team of researchers at London's King's College tested 800 13 and 14-year-olds …