A national ballot of members of NATFHE, the lecturers' union, found 43 per cent in favour of accepting the agreement and 57 per cent against. But only 10,000 of the union's 46,000 further education members voted - making the margin of defeat 1,300 votes.
Fifty-three per cent of members who responded to the ballot said they would be prepared to take industrial action, although the spectre of strikes will not arise until the New Year and only then after another ballot. A union conference earlier this month turned down a 2.7 per cent pay offer also contained in the framework agreement.
The union will resume talks with the Association of Colleges next week in an effort to reach a consensus on a contract more acceptable to its members.
The 60-page framework agreement, thrashed out during 12 days of intensive negotiations in July, had raised hopes of an end to five years of conflict. The agreement set out a maximum teaching week of 27 hours, 50 days annual holiday, entitlements to staff development and new arrangements for redundancy and union recognition. It included plans for joint working parties on a range of issues and would have safeguarded locally-agreed contracts at 200 colleges.
But the sticking point was always likely to be the requirement for 22 to 27 weekly teaching hours, which at the time NATFHE called "excessive" but "the best that could be achieved".
Paula Lanning, NATFHE's head of communications, said that despite this latest setback, the union was anxious to reach a lasting agreement with college employers.
"There should be a national framework because if the Government's objectives on lifelong learning and the New Deal are to be delivered we need industrial relations peace and arrangements that are workable."
Expecting lecturers to teach for 27 hours a week was "unrealistic", she said. "There is a big problem with student retention and it is no good giving lecturers unreasonable workloads and then expecting them to give students the support they need."
NATFHE general secretary Paul Mackney said: "Our members are saying loud and clear that the proposed weekly national lecturing hours of 22 to 27 hours are too high.
"Colleges need a national framework of working conditions to restore, throughout the further education system, partnership, morale and the sheer physical ability for all staff to deliver the Government's ambitious lifelong learning plans."
But the result is sure to test the patience of minister for lifelong learning Baroness Blackstone, who wrote to AOC acting chief executive Sue Dutton after the national framework had been agreed, saying it was "long overdue" and urging the two sides to make confrontation a thing of the past.
Mr Mackney said the appointment of a new AoC chief executive, expected any day now, "offers an opportunity for some fresh thinking to bring about a settlement".
The association's director of professional services, Marcia Roberts said the result was "disappointing but not unexpected". She said she was neither optimistic nor pessimistic for peace.
"We would wish to see an end to this dispute but it does seem as if the substantive issues that have divided us over the last five years are still there."