The highest-achieving were Brooke Weston CTC in Corby, with 80 per cent, Emmanuel CTC in Gateshead (79 per cent), and Thomas Telford CTC in Telford (76 per cent), figures produced by the Technology Colleges Trust showed.

Sir Cyril Taylor, the trust’s chairman, says the results show that the CTC policies, which include concentrating on technology, science and maths and encouraging close links with industrial sponsors, are “a proven winner in raising standards”.

But the figures show that a third of CTCs, hailed as “beacons of excellence” that would inspire other schools when they were launched in 1988, have failed to reach the national GCSE average.

At the lowest-scoring college, Leigh CTC in Dartford, Kent, only 26 per cent of pupils gained five or more top grades, putting it on a par with some low-achieving inner-city schools. And at the CTC in the Tory borough of Wandsworth, results have worsened since last year, with the percentage of top GCSE grades falling from 51 per cent to 47 per cent.

A spokeswoman for the trust said the low scorers were still mainly above the average for schools in their local authority areas. All CTCs are comprehensive in intake but were often competing with selective schools.

“We are extremely pleased with the results and delighted that those not showing the best results are nevertheless on an improving trend,” she said.

Labour’s shadow education secretary, David Blunkett, is expected to tell a conference organised by the Technology Colleges Trust in Bradford today that he wants to see more schools developing the specialisms of CTCs and technology schools.