Politicians' jibes about the contrast between highly paid plumbers and unemployable graduates have led to a boom in applications for plumbing courses.
Colleges were flooded with inquiries after media promises of secure employment and the chance to earn more than £100,000 a year.
Oxbridge graduates who have been working in the financial sector and are seeking a career change are among 4,000 people who applied for just 150 places to train as plumbers at the College of North West London this autumn.
New figures from City and Guilds, which accredits the majority of plumbing courses, show registrations up this year by 63 per cent nationally, while the number of students gaining plumbing certificates has risen by 44 per cent. Pat Leavey, deputy head of the faculty of technology at North West London, said the surge in applications followed national publicity about lucrative career opportunities in plumbing and news of the success of last year's cohort of students, 88 per cent of whom passed their exams.
Unsuccessful applicants who seek places elsewhere may be disappointed because cutbacks in further education courses catering for the construction industry over the past ten years had left colleges struggling to meet demand, he added.
He said: "It has been challenging and difficult to say to large numbers of keen people that unfortunately at the moment we cannot accommodate them."
The college is in discussions with the Learning and Skills Council about how it can increase the number of places on offer.
The plumbing boom reflects a general increase in demand for places on vocational courses.
City and Guilds says registrations for its courses overall have gone up by 20 per cent in the past 12 months. Some areas have experienced even greater growth. Applications for places on cleaning courses are up 80 per cent.