But how does an organisation that considers itself the national union for the profession get into bed with the other teaching unions?
Can the hard-left faction of the National Union of Teachers ever sit alongside the traditionally more moderate members of the Association of Teachers and Lecturers?
And while union leaders might pontificate in public on the need for professional unity, which one would truthfully be prepared to give up office to further the cause?
The call for a single trade union to represent teachers is not new.
Now, however, the NUT is balloting its members on proposals for a single union. And Doug McAvoy, its general secretary, and Peter Smith, general secretary of the Association of Teachers and Lecturers, last weekend spoke on the issue at an open meeting at the TUC.
Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, was invited to the meeting but refused to attend.
He insisted that there was no official NASUWT representative at the meeting, which was organised by a group called Professional Unity 2000, although Brian Williams, president of the union's Cardiff branch, was there.
"We have considered this (professional unity) at conferences, and the proposal was voted down decisively three or four years ago," said Mr de Gruchy.
Professional Unity 2000, set up after last year's teacher conferences, aims to ensure that the unions merge before the millennium.
It has already distributed 6,000 copies of its broadsheet Unite to every branch of three main unions, gained 33 affiliates and around a dozen people have paid Pounds 50 each to become patrons.
It has three honorary presidents: Roger Green, past national president of the ATL, Brian Williams from the NASUWT, and Malcolm Horne, past national president of the NUT.
"There is no doubt that the profession would be better safeguarded if there was a single union," said Mr Horne. "The way it has been treated by politicians and the media wouldn't have happened if the unions hadn't been so busy fighting among themselves for members."
Talk of professional unity goes back at least 20 years, and there has been backing from NUT conference delegates for decades.
"We could go out of business in support of the creation of a single organisation," said Mr McAvoy. "And we think that organisation should be the body that determines its own policies and affiliates."
Last year, leaders of the teaching unions put aside their internecine squabblings to present a joint submission to the teachers' pay review body.
But it wasn't long before the ATL and the NASUWT were back at each other's throats. This time the battle was sparked by the dispute at Manton junior school involving pupil Matthew Wilson.
Peter Smith, from the ATL, hit out at the NASUWT whose members accused the 10-year-old of threatening behaviour, staged a one-day strike and refused to accept him back into class. "The state funds schools to employ teachers to teach all children, not just those who are as good as gold," he said.
The NASUWT and NUT have long vied to become the biggest union. The calculation of union figures always causes debate. Figures submitted to the independent national certification office for 1995 show that the NUT had 192,009 members, the NASUWT 157,146 and the ATL, 130,339.
Just 100 people turned up to last weekend's meeting at the TUC, although Professional Unity 2000 claims affiliates from as far afield as East Cornwall, Lancashire, Wales and Devon.
Brian Williams, of the NASUWT, told the conference: "Most teachers want unity. When we held a ballot in my school the result was 74 for and only four against. Other schools should do the same and let their leaders know." He may have a job convincing Mr de Gruchy.