A government crackdown on sickness retirement amongst public sector workers has prompted union leaders to hit back by telling ministers that they are unfairly attacking workers such as teachers.

A Treasury report describing 22,000 public sector early retirements every year as "unacceptably high" has just been published. The current figure has fallen from a high of 40,000 in the mid-1990s. Ministers are believed to consider that the early retirement system is being abused, particularly by the public sector, and that they are considering ways of reducing the estimated £1 billion a year that it costs the taxpayer.

The government has been keen to stress that the issue is one which peaked under the previous Tory government.

Unions representing public sector workers such as teachers, civil servants and fire fighters said that the figures were not based on facts and that they were disappointed at the government attack.

A government spokesman is reported to have said, "no one is saying that ill-health retirement should not be available for genuine cases. We are determined to cut the bill and get the money to where it is most needed - in front-line services."