Growing numbers of state schools are abandoning the GCSE exam in favour of its rival designed along the lines of the traditional O-level.
New figures show that just over 650 schools are now sitting the International GCSE exam devised by Cambridge International Examinations (CiE).
The figures show the numbers have more than trebled in the past two years with the biggest increase in take-up being in the state sector.
Up until the last election, only 16 state schools were among the 200 taking the exam as rules forbade them from using public finance for them. Now, according to Ann Puntis, chief executive of CiE, part of Cambridge University, the split is even with 350 independent and 320 state schools.
A second exam board offering the IGCSE, Edexcel, has seen its numbers swell from just over 500 to 1,030 over a similar period.
Schools said that the IGCSE – which eschews coursework and concentrates more on open-ended exam questions to test critical thinking skills – were a better preparation for A-levels. Ms Puntis said the most popular subjects for schools transferring were those with essay-style questions such as English, modern foreign languages and history.