A 15-year-old was arrested for having a knife in his underpants during a huge police swoop.

The youngster was held after being searched in Islington as part of the Met’s London-wide Big Wing operation.

Another teenager, 17, was arrested in the borough after officers found a loaded gun hidden in a moped outside his house.

Today’s operation, targeting knife crime, involved around 5,800 police officers – 140 arrests have been made so far.

Temporary Det Chf Sup Gordon Allison, Head of Trident, which leads the Met’s response to gang and serious youth violence, said: “We have seen significant reductions in both gun and knife crime in recent years, however we recognise that knife crime continues to have a considerable impact.”

He added: “We support government proposals for tougher sentencing for knife crime offenders, and this week’s big wing gives us an opportunity to highlight some of our enforcement and prevention work.”

Comm Stephen Watson, leading today’s operation, said: “Knife crime cuts across several crime types such as robbery, burglary and gang crime. Work continues day in and day out alongside our partners to target those responsible but highly visible operations such as Operation Big Wing play a major part in the fight against all crime across London.”