Paul Mackney is offering to step down as general secretary of lecturers' union Natfhe to smooth the way for a merger with the Association of University Teachers.
His announcement came this week as a THES survey showed overwhelming support - more than 96 per cent - for a single lecturers' union among Natfhe's grassroots activists in higher education.
But grassroots AUT members, while broadly supportive of unity, are concerned that a merger could amount to a takeover by Natfhe, which is seen as more militant and more focused on further education than the AUT. Natfhe also has more members.
Mr Mackney, who was previously a further education lecturer and a regional Natfhe official for the union's further education sector, said he would step down if future merger talks stalled over the AUT's takeover fears.
Mr Mackney said: "Concerns that Natfhe is bigger, or dominated by further education, or that a merger might mean a Natfhe takeover have been problems. If that is stopping a merger, and my position is a problem, we could get that out of the way straight away. I would stand down."
Natfhe has used the departure of AUT general secretary David Triesman to step up its drive for merger. Speculation over who is to replace Mr Triesman has focused on the merger issue.
Natfhe has 65,000 members, with some 46,000 in further education colleges, 19,000 in post-1992 universities and about 1,000 in old universities. The AUT's 43,000 members are all in pre-1992 universities.
Mr Mackney said that further education was more likely to lose clout within a merged union. A merged union would have 62,000 higher education members and 46,000 college members.
But he said the merged union would have independent further and higher education wings. And he said the further and higher education divide was being bridged.
"Around 16 per cent of higher education is now taught in further education colleges," Mr Mackney said. This would increase with the launch of foundation degrees, he said.
The THES 's survey of Natfhe branch chiefs showed that only two of the 55 who responded were opposed to merger.
Paul Humphries, branch chair at University College Worcester, said: "I think the two unions serve quite different member needs. I also think it would further marginalise the further education sector."
Most respondents said a merger was long overdue. Dick Pitt, branch president at Sheffield Hallam University, said: "All workers in an industry have a common interest in joining together to oppose the more thuggish elements of management."
Some said merger was inevitable following the reform of the pay-bargaining machinery in the wake of the Bett report. This means the AUT and Natfhe will be united around the same pay negotiation table for the first time.
Keith Guest, branch secretary of Luton University, said: "Given the obvious closer links developing from the Bett report and the ultimate cessation of hostilities between the old and new sectors - a couple of centuries should do it - I would have thought the merger was inevitable."
There was concern about preserving the national contract on terms and conditions that exists in new universities but not in old. Richard Kirkwood, negotiating secretary at the University of North London, said the post-1992 contract "would need to be respected and constitutionally guaranteed in any merged organisation".