Kay Driver, the deputy general secretary of the Secondary Heads Association, has been chosen by the council of the Professional Association of Teachers as its “preferred candidate” for the leadership.

She was picked from a short-list of six and if unopposed, she will become the union’s general secretary. If there is a rival bid, PAT’s membership will be balloted. Ms Driver replaces John Andrews, who left unexpectedly with a cheque and “gagging order”.

The announcement came just two weeks after Ms Driver’s union, SHA, advertised for a new general secretary. The incumbent, John Sutton, is retiring, which leaves John Dunford, a former SHA president, as the firm favourite to take over.

Mr Dunford, head of Durham Johnston comprehensive, Durham, says he has not made his mind up yet whether to apply for the post. But the clever money is going on his name.

Bruce Douglas, the president, said he would have considered applying, but his position puts him on the appointment committee.

The union has traditionally appointed internally, and there is pressure for the next leader to be a serving head or college principal. There is also tension within the union between those who want a leader who will promote closer co-operation with the rival National Association of Head Teachers, and others who prefer one who will keep it at arm’s length.

But with February 18 as the closing date for applications, the union has given itself a tight timescale for heads who would have to give in their notice by May.

Dame Tamsyn Imison, a member of the union’s council, said: “We need someone with a high profile, but who also knows what running a school or college is like. We need someone who can provide quality advice - the union’s hotline is a vital service - and also raise the union’s profile nationally.”

Other members say the union needs a big hitter to take on David Hart, NAHT general secretary, who enjoys a high profile in the media. John Sutton has always maintained SHA’s structure made it more difficult for him to sound off on policy, while Mr Hart is given a freer hand.

SHA has 6,696 full-paying members and its base is declining. The number of schools is decreasing as is the total of deputy heads, and the union has opened its membership to other school management categories. Its management courses and publications are popular, although a substantial number of its members also belong to the NAHT.

Mr Dunford was a popular, well-known figure during his presidency. As general secretary he would encourage greater involvement with the NAHT. He specialised in reform of the 14 to 19 curriculum and said Sir Ron Dearing’s report (on 16 to 19 education) was not bold enough.

He was awarded a PhD for a thesis on HM Inspectorate and has had a number of historical studies published. During his first meeting with the education press as president, he announced that John Major, then prime minister, had not put a foot right on education.

Mr Dunford may face challenges from other members who have yet to show their hand, and there is always the threat of outside candidates - John Akker, recently deposed general secretary of the lecturers’ union, NATFHE, is now back in the job market.

Kay Driver’s move from SHA to PAT is by no means certain. History shows that being the union’s preferred candidate does not necessarily mean the job is in the bag.

In 1992, John Andrews emerged winner in a ballot, beating the union council’s choice. The 32,000-strong association is commonly known as the “no-strike” union and has a strongly Christian wing.

A merger with the Association of Teachers and Lecturers foundered seven years ago, but rumours suggest takeover ambitions have not been put to rest.

However among union officials, PAT has earned itself the nickname Son of Nigel, a reference to its support of the National Association of Schoolmasters Union of Women Teachers’ position on Department for Education and Employment committees.