The New Engineering Foundation said the subject had fared worst in the battle for resources, leading to inadequate staff training budgets and a shortage of technicians.

Colleges see engineering as a declining area and are in “survival mode”, according to the charity, which campaigns and provides grants to encourage the study of engineering.

Professor Sa’ad Medhat, chief executive of the NEF, said: “Engineering has always been at the heart of the college system. But this heart is breaking.”

When staff were asked if they would attend paid-for professional development courses, 48 per cent said no, blaming pressure of work. One head of department told researchers: “We have had the same working group for over five years and they are all in their 50s. When one of them retired last year, I couldn’t find a replacement with the right experience.”

The study, based on a survey of a fifth of English colleges, also identified causes for optimism, praising several thriving departments and centres of vocational excellence. Many colleges were successful at covering a wide and varied range of niche interests in engineering and are working with employers to share equipment.

New courses, such as Blackburn College’s on digital broadcast engineering, have proved more successful than traditional “metal-bashing”.