During the five years up to March 2001, more than 97,000 qualified teachers left teaching, some straight after completing their training. This equates to almost 25 per cent of the active teaching force.

Some left in 1996, immediately before the introduction of stricter pension rules that made it harder to retire early. However, these probably account for no more than a quarter of those who quit during this period.

More disturbingly, nearly 36,000 teachers aged 25 to 39 quit between 1996 and 2001 - an attrition rate of 7,000 a year. A further 13,000 newly-qualified teachers in this age bracket, around 2,500 a year, never even made it into the classroom.

We need to know more about these missing and departing teachers. Were they the potential leaders of tomorrow - fed up with paperwork and a lack of discipline - or would they have ended up in Charles Clarke’s army of under-performing teachers?

Some of the younger teachers will not be entirely lost to the service, having taken up other posts in the education sector. Between 1996 and 2001 about 50 local education authorities were created, each needing several tiers of management. Other posts sprang up because of new initiatives such as education action zones and the literacy hour. If only a small percentage of younger teachers filling such posts could be lured back to schools staffing problems might be eased.

However, as the recent General Teaching Council for England survey shows, many teachers are not committed to staying. Much has been done to recruit new teachers but more attention must now be paid to retention. Solving the workload crisis would be a good start.

John Howson is a director of Education Data Surveys