A man was stabbed in the neck with a broken bottle as violence broke out at a BlackBerry BBM Party in a South Bank nightclub in London.

A man in his 30s was taken to hospital and is believed to be critically injured. The stabbing happened just yards from where an IBTimes UK reporter was standing. The scuffle broke out just after Jessie J finished her set.

The event, billed as a journalist and celebrity-only party, was overcrowded.

Benjamin Cohen, Channel 4's technology correspondent, said: "Everyone tried to leave at the same time but the organisers weren't geared up for it, and there was a huge rush to get to the cloakroom.

"People were crying and quite a lot were being sick, whether from the blood or the alcohol. A lot of people here were teen users of BlackBerry who don't seem to have had a free drink before."

Police kept people inside the club for at least an hour after the party was shut down.

Both BlackBerry and the Metropolitan Police were unavailable for comment.