Millions of scripts have to be checked in the summer

The AQA, OCR and Edexcel campaign comes after 24 million scripts had to be checked in 2003.

Post-graduate students have already been used as examiners in an effort to prevent staff shortages.

The joint website will allow experts in all subject areas - not just teachers - to apply.

'Useful insights'

The Qualifications and Curriculum Authority, the exams watchdog for England, is helping to run the site.

The chief executive, Ken Boston, said it was also important to retain current markers.

He added: "The recruitment campaign will draw attention to the benefits of being an examiner, while recognising the professional role that examiners undertake each year.

"Examining can provide useful insights into how students' performances can be improved, provide fresh ideas to use in the classroom and increase teachers' professional credentials. It is important that we encourage new people to become examiners and markers."

Examiners have criticised the current system as "overloaded".

Dr Boston once described it as a "cottage industry" and called for more centralised marking and moderating.