Three people are critically injured after a crush at a gig in Brixton, south London. How did it happen?

While many details are still unclear, the BBC has pieced together this account from verified social media videos and eyewitness accounts.

Before the show

Doors at the O2 Academy Brixton were due to open at 19:00 GMT for the show by Nigerian Afrobeats singer Asake. An update from the artist's Twitter account ahead of the first of a run of shows at the venue promised DJs playing from 19:15 but warned: "Please do not come to Brixton Academy if you do not have a valid ticket."

It promised the "usual security measures" would be in place.

Crowds build outside

On Thursday night, video posted by about 20:00 outside the Brixton Academy showed only a relatively small number of people were gathered outside.

But TikTok user yupitslydia posted a video showing what she said was the scene at 21:17. By that point, a crowd of hundreds was shut out of the venue. "They're not letting anyone inside and the queue is all around the building," she said.

I thought I was going die - Brixton crush victim

Police say they were called at about 21:30. A video uploaded to Twitter at that time shows a large but apparently peaceful crowd completely filling what seems to be one of the alleys by the side of the venue.

"The police have locked off Asake and have left a bunch of people in an alley in the freezing cold," said the Twitter user, @__93_Mide.

A crush - then the crowd bursts inside

One video shows what it was like right by the locked doors of the venue. Twitter user DammySNM posted it with the message: "They need to close down o2 Brixton."

In the footage, people are packed tightly up against the doors and appear to be jostling with each other to create space. The crowd surges slightly one way and then the other as people seem to push bacK