Sadiq Khan, London’s Mayor, said he will set up late-night youth clubs across the capital in the wake of the chaos in Clapham, to “give young Londoners somewhere safe to go, opportunities to help them fulfil their potential, and give them the support of teams of trusted adults”.

Hall blamed Rachel Reeves, the Chancellor, for putting bosses off hiring inexperienced youngsters by raising taxes, minimum wages and imposing fresh red tape.

“Youth unemployment was always going to go up when the National Insurance hike was put in. Never have I been so shocked that somebody who wants to grow the economy then goes and clobbers the employers – who are not then going to employ people without experience,” says Hall. “That is the youth.”

Companies have to invest in training those who have just left, or are still at, school, college, and university. Ramping up the cost of taking them on erodes any remaining incentive to hire them in the first place.

When this leads to the death of the Saturday job, it leaves large numbers of teenagers idle, frustrated, poor and prospectless. Instead of earning in their evenings and weekends, it is all too easy to find trouble in hours of scrolling social media.

The circumstances are uncomfortably close to those which surrounded the 2011 riots, which began in London but spread to other parts of the country.

A report published the following year highlighted high and sustained youth unemployment, which left swathes of the population with “a lack of hopes and dreams for the future”.

“In some areas over 61pc of rioters were unemployed,” it found.