More than half a million young Britons are officially too sick to work and claiming incapacity benefits, a higher tally than the number claiming unemployment benefit, according to figures obtained by the Financial Times.

The figure, which includes more than 300,000 young people claiming for “mental and behavioural disorders”, shows continuing high levels of worklessness among the young, in spite of 10 years of steady economic growth and a concerted attempt to move people off welfare and into work.