The gloves are off as the lecturers’ union NATFHE warns that its members are likely to be on the brink of a two-day walk-out by the time employers return to the negotiating table on May 20 - and more action could follow.

The Association of Colleges - which made the offer on behalf of principals on Tuesday - admits the amount of cash on the table reflects a “crisis” which can only be solved with more government funding.

Even the moderate Association for College Management says the AOC would have been wiser to have made no offer than one of only 1.5 per cent.

NATFHE says lecturers’ pay, compared with schoolteachers, is making nonsense of plans to increase college involvement in vocational education at 14-plus.

“People won’t be happy working alongside others when there is a 12 per cent pay gap,” said Paul Mackney, NATFHE’s general secretary. “And that figure is from the department, so it is probably conservative, just like the Government.”

He said the Government’s performance on lecturers’ pay had become a “shambles”, with some highly experienced staff quitting to find more lucrative positions in schools.

The ACM said lack of funding had given the AOC little room for manoeuvre, but added that the offer was “unwise”, particularly as it comes just before the lobby of Parliament on Tuesday, when employers and unions will be presenting a united front on pay.

“All the unions were very upset,” said ACM general secretary Peter Pendle.

The unions want parity with schoolteachers, a minimum pound;11,000 starting salary for support staff, a pound;4,000 London weighting allowance, and a maximum 35-hour working week.

NATFHE expects that the two days of action will take place between May 22 and 31.

Ivor Jones, AOC director of employment policy, said: “The offer is based on what our members say they can afford.”

Strike looms in Wales, 35