It was Doug McAvoy, general secretary of the National Union of Teachers, who started the Trotskyite hare running. He blamed activists taking over the union at division level and hijacking conference from the average classroom teacher.

A Sunday Times report duly showed a map of Britain’s “hard left targets” which included Buckinghamshire, Berkshire, Cumbria and Devon.

NUT insiders have accused Mr McAvoy of being disingenuous. Brian Carter, a regional official, said the real issue was a mismatch between the long-term strategy of the national union and the sense of frustration of members faced with dealing with redundancies and anger about class size.

He said: “The pent-up feelings of members were released at conference. They know that the crisis in their schools is not caused by the school management or the local education authority - it is the Government. They also believe they have the support of parents to take action. But Doug McAvoy sees action as damaging.”

A brief look at the union’s accounts indicates the strategy of the leadership. The “strike” fund contains just Pounds 3 million, hardly enough to support members taking prolonged action. What has increased is spending on Parliamentary lobbying.

The union has also hired the services of Sir Tim Bell’s public relations company Lowe Bell Communications. It has turned to the friend of Lady and Mark Thatcher to advise on preparations for the union’s 125th anniversary in July. The intention is to look at the way the union campaigns and the reputation it has with the public. And following the events in Blackpool Mr McAvoy will be looking at ways to salvage the NUT’s reputation.

Bernard Regan, a member of the executive and Socialist Teachers’ Alliance, said: “The Broad Left majority on the executive are anticipating the election of a Labour Government and want to put the NUT in the position of the Labour party at school. They are anxious not to do anything that can be perceived as presenting the Labour party with an electoral problem.

“But others in the union are not convinced that the Labour party has put forward coherent policies to support, and want action on things that are happening now.”

The ballot for a one-day strike on class size was opposed by the leadership.

The majorities shown by the votes against the executive motions and amendments at conference do not suggest that the balance lies in the hands of a number of extremists. Rather they show that the traditional left-wing groups within the union’s organisation are gaining support.

Mr McAvoy intends to gain ground from the left by having more surveys of the whole membership on key issues. He believes the results will show the majority to be more in tune with the leadership than political groups which dominate policy-making at conference.

The NUT has long been dogged with factionalism. At present the Broad Left is in control of the national executive with two-thirds of the vote.

Its group consists of a hotchpotch of reconstructed communists and right-wing Labour. Mr McAvoy is not a member but works with them to mutual benefit. Steve Sinnott, deputy general secretary, is the Broad Left’s great hope for taking on Mr McAvoy’s mantle when he retires.

The two main groupings on the left are the Campaign for a Democratic and Fighting Union and the Socialist Teachers’ Alliance, of which Carole Regan, next year’s president is a leading light.

The CDFU, founded in 1987, describes itself as a non-ideological group opposed to the union leadership’s “rightward turn” from 1986 onwards (when the NUT ended the mid-1980s pay dispute through ACAS). There are fewer than 100 members, paying a Pounds 12 subscription fee, according to Howard Roberts, former executive member. He describes the CDFU as a ginger group for local association and division leaders.

The STA contains individuals and groups sharing a socialist agenda and it costs Pounds 20 to join. Its members hail from the left of the Labour party to Socialist Organiser and various obscure Marxist groups.

It has in recent years been beset with a battle within its ranks with the Socialist Workers Party. STA members now say that the SWP no longer takes an active role within the organisation.

While the STA and CDFU vote largely the same way, personal wrangles and political differences have so far prevented them putting up a united front against the leadership they both oppose.

Mr McAvoy will be hoping to avert the one-day strike. And while he was routed at conference, he is not left with many decisions that will cause him problems.

The problem that won’t go away, however, is the union’s poor image, which he acknowledges could lead to teacher resignations which the NUT can ill afford.