IF the Colne Valley high school, Linthwaite, near Huddersfield, is anything to go by, talk of teacher union unity is becoming irresistible.

“If we want the same sort of deal as Scottish teachers, we have to get together and sort it out among ourselves,” says Trevor Woolley, the Association of Teachers and Lecturers’ representative at the school, adding that the unions will come together: “Yes, they will - there is a drift towards it.”

Terry Hindson, the National Association of Schoolmasters Union of Women Teachers’ rep, has reservations but says: “It is really logical to have one union which would promote a strong public image of the profession. The grass roots are for it.”

“Wherever possible the three of us try to work together,” says Joanne Pearson, National Union of Teachers’ rep at the school. She adds: “It would be much easier if we could follow the same guidelines.”

She believes that working together strengthens their case: “Snide comments about each other at the national level do not help our professional image or relations with the Government.”

A simple aggregation of teacher numbers illustrates what undoubted power they could wield. The latest official figures for the big three teacher unions show that they claim a total of 729,837 members (including students and retired members) - almost 10 per cent of all trade unionists in the country.

Group together the largest nine unions including the Educational Institute of Scotland (EIS) (see table 1) and almost one million employees are trade union members working in education.

What is also clear is their combined economic strength. The annual income of the three main unions is just under pound;44 million, the top nine pound;69m. The big three declare assets valued at pound;46m, while the top nine have assets worth pound;78m.

The pay of general secretaries in the teacher unions historically attract controversy. Teachers in the main classroom unions spend well over pound;250,000 on the pay and benefits of their three top officials. If the top nine education union bosses are included, annual spending on general secretaries nudges pound;700,000.

The logic of merger is accepted elsewhere. At a time when membership of trade unions has grown, the TUC reports that the national trend is for further concentration.

It is encouraging what it calls “programmes of quiet conversion” to merger. Talks will begin next month when leaders of the three big classroom unions meet John Monks, the TUC general secretary to discuss a timetable. TUC sources see the apparent softening of attitude towards unity from the NASUWT as a “golden opportunity” for the unions to address mergers.

The Government is also in favour of unity. A former adviser says ministers would prefer “a balanced approach”, better delivered by one strong voice, than the current race by one or more unions to provide a soundbite opposing every initiative.

But the backing of many union members - 71 per cent according to this week’s TES poll - the TUC and the Government does not mean that it will be easy to achieve. Each union has its own raison d’etre for existence, its own culture and values and its own version of brand loyalty.

This tribalism, as one general secretary describes it, is the key to understanding the obstacles to unity. NASUWT members, for example, consider the NUT to be more of a political party than a trade union.

The unions’ rules and structure also work against change. The election of general secretaries for five-year terms and the system whereby presidents are elected for four-year terms builds in inertia.

The existence of large national executive committees means that in the big three unions alone there are hundreds of turkeys who need to be persuaded of the benefits of voting for a selected cull at Christmas.

Add to those the large numbers of elected branch officials throughout every local education authority, all of whom feel an intense brand loyalty. Activists are likely to be less keen than ordinary members.

Then there are the financial assets, which range from outright ownership of office and conference facilities to extensive investments in the stock market.

Staffing presents a challenge: no trade unionist would accept staff casualties. Another potential point of conflict will be the unions’

constitutions. Membership rules about heads and teaching assistants are but two issues that are likely to bring tribalism to a head.

So what are the prospects for unity? The enthusiasm among union members is clear. The reality is that, although co-operation varies from area to area, at the school and local levels a good degree of it exists.

Nationally, the rivalries regularly receive the glare of publicity and yet there, too, union leaders often work closely together. The entry of ATL into the TUC has led to a closer relationship between the three large classroom unions, with the formulation of joint policy resolutions to Congress includes students and retired members.

The NASUWT, so far the least unity-minded of the three, has declared it wants a debate. And the most positive indication yet of a growing desire to work together was the recent joint oral evidence on teachers’ workload to the School Teachers’ Review Body, which involved each of the big three general secretaries.

But it is retirements that could provide the biggest impetus. Nigel de Gruchy retires as general secretary of the NASUWT this Easter and his successor, Eamonn O’Kane, takes a much more positive stance.

Over the next five years Doug McAvoy retires from the NUT, Peter Smith from ATL, David Hart from the NAHT and Eamonn O’Kane is expected to fulfil a caretaker role at NASUWT before retiring.

The main stumbling block may be Mr O’Kane‘s executive, some of whom are already upset about his pro-unity paper.

The process could be set in motion if this Easter’s conferences decide to set up working groups. If the executives were to agree within the next 12 months, the proposals would go to next Easter’s union conferences: a two-thirds majority at each would be needed. After that, a simple majority of members in favour would be enough for the NUT and a two-thirds majority for the NASUWT.

If the unions do go full steam for unity, who is the natural leader of the new super union? Other such mergers show that what is most likely is a troika of general secretaries managing the new entity in the short term.

It is likely that one of a new breed of teacher leaders will inherit the prize. The smart money is on John Bangs of the NUT or Chris Keates of the NASUWT - if they succeed the current general secretaries.

Many national executive members oppose unity. But unions are democratic organisations and a groundswell of member opinion, with yet more change imposed by the Government on education, will lead to new professional groupings and further and higher education unions.

Once the debate begins in earnest, unity will be irresistible. In five years’ time the landscape will have changed forever.