While almost all the other teaching unions have gradually retreated from all-out industrial war against the government's plans to overhaul teachers' pensions, the NUT has continued to spearhead the fight against the measures. At the union's annual conference in Torquay last month, members agreed to plan for a one-day national strike before the end of June.
But last Thursday, while hundreds of thousands of public sector workers went out on strike, school teachers were at their desks as usual. And at exactly the same time, the NUT executive decided to overrule a conference resolution and shelve plans for a June strike. Instead, it decided that the union should look into taking action in the autumn.
Although much NUT rhetoric is as fiery as ever, this is the third time the union has stepped back from the brink in recent months. Calls for strike action on 1 March were snubbed and a proposed national strike on 28 March was scaled down, eventually only taking place in the union's London heartland. Now the June strike is off, prompting questions about whether the union's leadership recognises that it has misjudged members' appetite for industrial action.
"The decision essentially came down to the fact that the NUT would have been the only classroom union involved," said deputy general secretary Kevin Courtney. "We want to go back to all the other trade unions who haven't signed up (to the current deal on the table) and talk about taking action together.
"With local pay, performance-related pay and the changes to capability procedures, we think teachers are under attack more than they have been for a long time."
The decision to abandon the planned walkout followed a survey of regional secretaries and, most tellingly, was made in the light of "positive work" with the NASUWT teaching union, which has already signalled its preference to wait until the autumn, almost a year on from the last national strike.
The NUT is also planning to hold a new ballot for strike and non-strike action over pensions and several other issues, including proposals to introduce regional pay.
A counterproposal at the executive meeting last week, which was backed by the NUT's left-wing factions and would have meant pressing ahead with the June strike, was narrowly defeated. "I think that was a mistake," said supporter and executive member Martin Powell-Davies. "The fact is that many other unions took action on 10 May. I think we should be working with the other unions to put the government under pressure. There are more concessions to be won."
The NUT has struggled to maintain the momentum in its pensions campaign, according to Professor Howard Stevenson, deputy director of the University of Lincoln's centre for educational research and development.
"Some members are quite clearly wanting more action and are frustrated; others are reluctant to take action without the other unions," Professor Stevenson said. "At times, the unions compete to out-militant each other, but at other times it encourages timidity, as they don't want to go out on a limb.
"The physical action of placing a cross on a piece of paper is a galvanising experience, and the NUT is trying to re-energise the campaign."
Although Professor Stevenson thinks that the unions have failed to exert any substantial pressure on ministers thus far, he believes that, following a poor showing in the local elections, the unions have the ability to ratchet up the pressure on a weakened government.
"Their confidence will start to diminish. If things don't improve for the government, and the teaching unions take united action, it could find itself in a difficult position," he added.
From a resolution agreed by delegates at the NUT conference: "Conference believes that the strike action taken by the union and others on 30 June and again on 30 November, which galvanised the trade union movement and won concessions from government, has shown that our campaign can succeed."