The Scottish Secondary Teachers’ Association, which claims a membership of around 9,000, has announced a “work to contract” in response to government plans to reform pensions.

From 15 May, SSTA members will have to negotiate with their line managers which tasks beyond their 35-hour working week they will not do, said general secretary Ann Ballinger.

“Members will not be withdrawing labour or closing schools by this action. All duties included in working time agreements and capable of being completed within the 35-hour working week will be completed,” she added.

Just under 37.9 per cent of SSTA members known to be in employment responded to its ballot: 85.5 per cent voted yes to a work to contract; 14.2 per cent voted no.

The EIS union warned that further strike action was likely if neither the Scottish nor the UK government responded positively to its campaign.

“Such action will require the majority support of teachers in Scotland, which only the EIS is in a position to deliver,” said general secretary Larry Flanagan.

The EIS is pinning its hopes on negotiations with the Scottish government to produce a “Scottish solution” that improves on the UK pensions deal. The SSTA said a recent Treasury letter to the Scottish government made clear the intention of the UK Government to “ensure that Scottish teachers are treated as badly as their English and Welsh colleagues”.

Mrs Ballinger claimed the rise in pension contributions, which took effect last month, was already forcing some teachers to abandon the scheme.

A Scottish government spokesman said its discussions with unions and employers needed to be carefully considered, but it was also “mindful of the time constraints we face as a result of the limitations set by the UK government”.