Supporters of John Illingworth, who withdrew from the National Union of Teachers general secretary contest due to ill health, will meet in Nottingham tomorrow to see if they can agree on a new candidate.
Mr Illingworth had the backing of all three of the union's left-wing factions - the Campaign for a Democratic and Fighting Union, Socialist Teachers Alliance and the Socialist Workers Party.
But now they are struggling to reach a consensus. The STA and SWP have already decided that their preferred candidate would be Christine Blower, a former NUT president who put up a respectable performance when she stood for general secretary in 1999.
Ms Blower is also likely to enjoy considerable support from the CDFU of which she is a member. But the faction was waiting to see how Ian Murch, a leading CDFU member, performed in the ballot for NUT treasurer, due to be announced later this week, before deciding.
And if Ms Blower does not stand or if the CDFU opts for Mr Murch, who last ran for the leadership in 1989, then the STA will go for Alex Kenney, its convenor, and the SWP is likely to follow suit. They do not believe that Mr Murch would do enough to back wider political campaigns such as pulling out troops from Iraq.
The fourth possibility is Martin Powell-Davies, another STA member. The Lewisham branch secretary is not backed by a faction but believes he could win the support of ordinary teachers. The two existing candidates in the leadership race are Steve Sinnott, the deputy general secretary backed by the soft-left Broadly Speaking faction, and John Bangs, the NUT's head of education and Mr McAvoy's preferred successor. Nominations for the June ballot must be in by May 3.