I N 2002 BRETT WIGDORTZ ,a young consultant, left McKinsey to set up Teach First. The idea was simple: to lure high-flyers, often from elite universities, to tough schools with the promise of networking, quick training and good career opportunities for those who left after a few years. Since then the charity has worked with the government to train around 10,000 teachers, many of whom have gone on to big jobs in the education system.

Now Teach First is branching out. On November 20th it announced that it would establish three new strands. One will be aimed at those contemplating a change of career, another at those teachers who have quit the profession, and the third at classroom assistants who want to train as fully fledged teachers. Russell Hobby, the organisation’s new boss, reckons that in five years these new routes could account for a third of Teach First’s intake.

The need for more teachers is pressing enough to justify the wider focus. The government has failed to meet its recruitment targets for the past five years. Last year it fell short by 20%. The proportion of secondary-school teachers leaving the profession early has crept up, from 10.8% in 2010-11 to 11.8% in 2014-15. Worse, the Department for Education’s forecasts suggest that the number of pupils will shoot up over the next decade (see chart).