UCU targets 220,000 non-members in FE and HE l Only 35% are unionised compared with 60% in rest of public sector
The University and College Union is struggling to attract the youngest and lowest-paid lecturers.
More than one in 10 lecturers in further education are aged under 30, but this age group makes up less than four per cent of the UCU membership, according to a report leaked to FE Focus.
The union was formed by the merger of Natfhe and the AUT - whose combined membership was 117,000 in 2005.
While this number has held up, the report suggests this is increasingly reliant on older staff who are approaching retirement.
The document was produced for the union by Jeremy Waddington, professor of industrial relations at the University of Manchester. Just 35 per cent of eligible lecturers are members of the UCU, compared with 60 per cent of workers belonging to unions in the public sector as a whole.
Of those who are members, more than a third don't know if they have a rep at their workplace.
There are 220,000 further and higher education lecturers who are not members of the UCU, according to its own estimates.
The Association of Teachers and Lecturers has 7,500 members in FE. The Association for College Management has 4,000 members in FE and HE.
The UCU - and Natfhe before it - has been campaigning to narrow an estimated 10 per cent gap between the pay of lecturers and school teachers which has opened up since 1993.
On Wednesday, it staged a lunchtime protest outside colleges, and strike action is planned if there is no progress in negotiations with the Association of Colleges.
The report was not made public but Sally Hunt, UCU general secretary, admitted her concern over its contents in a speech at the union's annual congress in Manchester last week. She said: "There are far too many non- members in both further and higher education. "Those who need us most are those who currently are least likely to join us. That's a sobering thought."
Professor Waddington said in his report that satisfaction with workplace representation in UCU was lower than several other unions. But he added that FE, where 54 per cent were content, fared better than the universities, where the figure fell to less than 40 per cent.
The survey of 4,000 members found that the main motivations for staying in the union were the prospect of support if a problem arose at work, improvements in pay and conditions and a principled belief in the value of trade unionism.
Barry Lovejoy, the UCU's head of FE, claimed pressure of work had made reps less effective at recruitment than they should be.
He said the union will be trying to recruit representatives and to improve their training, in the hope that what they achieve in the workplace will attract new members.
The union is also planning to monitor recruitment on an area-by-area basis to assess the effects on the strength of its membership.
Professor Waddington's report found that members were more likely to be happy with the union when there was a strong local branch at their institution.
Coverage was "patchy" at the moment, he said. "The `value-added' to the union of the presence of a local representative is difficult to understate."
UCU conference report, page 3.