Three Metropolitan Police officers in the UK are being investigated over an alleged racist assault after a black teenager suffered a broken knee in a stop-and-search.

The 16-year-old boy was riding an e-bike in Tottenham, north London, in April last year when he was forcibly tackled to the ground by an officer part of a unit dedicated to phone thefts and other street crime.

Nothing was found on the teenager, but he was arrested on suspicion of several offences, including racially aggravated public order, threats to kill and dangerous driving, and taken to a local police station.

But the boy, who sources say was in agony, was refused detention as the custody sergeant was concerned about his injuries and was transferred to hospital, where he was diagnosed with a fractured knee.