The international research shows that in Swiss schools, where teachers are free to choose texts, pupils acquire language skills at a faster rate than their English peers.

Education Secretary David Blunkett has insisted that Shakespeare remains a compulsory part of secondary English, despite concern that 11 to 14-year-olds in particular often struggle with his work.

The Government is introducing new literacy and numeracy programmes to raise standards in the early secondary years but has no plans to downgrade Shakespeare’s key position in the English curriculum.

The research, to be published shortly by the National Institute of Economic and Social Research, says lower-ability English 14-year-olds are three years behind their Swiss peers in language skills development.

Researchers say the Swiss put more emphasis on thinking and discussion, give greater weight to mental and oral work and less to composition.

Professor Sig Prais who led the study, said the findings did not mean Shakespeare should be scrapped. But he did suggest that the amount of time pupils spent studying him might vary according to their abilities.

He said: “The true issue is whether his writings occupy an excessive part of the school timetable, and whether that part should vary according to pupils’ interests, mix of talents, and career aims and prospects.”

The national curriculum requires all 14-year-olds to read and be tested on a Shakespeare play. The only pupils exempted are the lowest tenth of the ability range. At GCSE, about a quarter of marks in English (often referred to as English language) are now allotted to questions about literary texts.

Rex Gibson, series editor of the Cambridge school Shakespeare series said he would be surprised if Swiss 14-year-olds did not get a hefty slice of their own literary canon.

“Most teachers in England would want to teach Shakespeare, but I’m sure they would prefer to have greater choice over which play, and the form of assessment at 14.”