retirement plans provides fresh evidence that secondary schools face a staffing crisis over the next decade, the union claims.

Findings from the questionnaire show that 29 per cent of respondents aim to retire before the age of 60 and a further 48 per cent at 60.

Critically, however, only 11 per cent of the 2,600 respondents (from a total membership of 8,800) said they were likely to do supply teaching after they retired - a response which the SSTA warns will exacerbate teacher shortages.

Jim Docherty, the union’s assistant general secretary, says that the findings fly in the face of proposals to lift the pension age for public sector workers -including teachers - to 65.

Mr Docherty said: “The responses totally refute the suggestion by the Government that a high significant number of workers wish to work beyond the age of 65 and totally defeats the Government’s basic assertions which led to the current proposals relating to pension arrangements.”

The SSTA, which has been one of the Scottish Executive’s sternest critics over workforce planning and teacher shortages, stated: “From the findings obtained, Scottish secondary education faces a severe problem in relation to teacher supply over at least the next decade. Even the most optimistic of estimates relating to recruitment indicate that there will be an extreme shortage of secondary teachers during at least that period.”

However, a spokeswoman for the Executive said: “Looking at the SSTA predictions of teacher shortages, there is nothing new or revolutionary about this. The pattern of retirals being predicted is no different from the past and is part of the workforce planning exercise.”

She added: “Far from decreasing, teacher numbers are increasing to 53,000 by 2007. Next term there should be 1,400 extra secondary teachers due to take up probationary posts.”

The survey found that, while on average 29 per cent of members wanted to take early retirement, in East Renfrewshire only 14 per cent had expressed interest in doing so.

“It does not take a genius to work out that East Renfrewshire, the authority with the lowest percentage of teachers wanting to leave early, represents the leafy suburbs and has fewer discipline problems and related stress,” Mr Docherty said.

Interest in early retirement in Glasgow secondaries was “average” but higher than average in North Lanarkshire.

The group with the highest interest in retiring at or before 60 was the principal teacher group, where 80 per cent fell into that category. Some 76 per cent of unpromoted main grade teachers wanted to retire at or before 60, as did 73 per cent of headteachers.