According to recent figures from the Department for Children, Schools and Families, the further south you live in England, the greater the likelihood that secondary schools will have worse staffing levels than their counterparts further north.

This is based upon an examination of pupilteacher ratios (PTR) for every local authority, published annually by the Government. PTRs are a crude measure, but offer a better overall picture of staff deployment than class sizes since they take into account the effects of non-contact time and the creation of some small teaching groups at either A-level or for pupils with special educational needs.

This year, Thurrock in Essex reported the worst PTR, at 19.1 pupils per teacher, compared with the average for England of 15.9. The East of England government office region as a whole (to which Thurrock belongs) had a PTR of 16.7, well above the national average. No local authority in the region has a better than average secondary PTR, although Norfolk and Suffolk, with many small rural schools, managed to do better than average in the primary sector.

Knowsley in Merseyside reported the best secondary PTR in England, with just 13.6 pupils per teacher, some 5.5 pupils per teacher better than in Thurrock. Indeed, the North West as a whole fares well. Bury, Trafford and Blackpool are the only three authorities in the North West with above-average secondary PTRs. How far PTRs reflect an effective model for school funding is something supporters of a pupil premium will ponder. But Knowsley ranked 68th out of the 529 Parliamentary constituencies in England for unemployment in August 2009, whereas Thurrock was placed 180th.

John Howson is a director of Education Data Surveys, part of TSL Education.