Members of a teaching union could take industrial action to get a reducation in class sizes.

Delegates at the annual conference of the National Association of Schoolmasters Union of Women Teachers (NASUWT) decided to campaign to extend infant class size limits of 30 to all school age groups.

A union report presented to the conference in Llandudno on Wednesday indicates that average class sizes in England are far worse than in other parts of the UK.

By adopting the report, delegates agreed that the union should authorise ballots for industrial action where large class sizes mean members are faced with "unreasonable workload demands".

The report says that only a relatively small number of countries, including India, the Philippines, Chile and Korea, have worse primary school pupil/teacher ratios.

Many countries also fare better in the secondary sector, it adds.

Rising numbers

It acknowledges that Labour has had "measured success" in fulfilling its election pledge of cutting infant class sizes to a maximum of 30.

But it says the number of junior school pupils in classes of over 30 has risen and then levelled out to just over a third of pupils, according to last year's figures from the Department for Education.

And the number of secondary school pupils in classes of over 30 has continued to rise, currently standing at more than 10% of pupils.

The report reiterates the union's policy that the maximum size of most school classes should be 26.

It says that the "only certain route" to making "significant and permanent improvements" in class sizes is for statutory limits to be established.

Conference delegates gave the union the go-ahead to try to persuade the government to extend the current class size limits to all age groups.

'Size matters'

Roger Kirk, the national executive member who introduced the report, said: "The government has made a start, we acknowledge that, but it is a very small start."

Another executive member, Sue Rogers, said: "Who says size doesn't matter? I know it, Blunkett knows it.

"The impact of a few extra children is out of all proportion to the reality of the problems you face."

The possibility of industrial action over class size-induced workloads ties in with the union's call for action to be taken over teachers' general workloads.

On Wednesday, delegates sanctioned a ballot to decide whether action should go ahead to ease the bureaucracy burden on teachers, which the union believes will be made much worse by the introduction of performance-related pay.