Research in Motion's (RIM) exclusive party in celebration of BlackBerry Messenger ended badly last night when a guest was stabbed.

According to a report by the Evening Standard, a man in his 30s was stabbed in the neck with a bottle shortly after Jessie J's headline set. It is further bad news after the firm reported a financial loss of $125 million.

RIM said: "A serious incident occurred involving a guest at a BlackBerry event tonight. Our first concern is the well-being of the individual concerned."

"We are doing all that we can to assist the police with their enquiries and are not able to provide any further comment at this time."

Witness Karen Jessop, 21, said: "I was standing right next to them. They began scuffling and everyone started moving back as you could tell things were about to kick off. But then he hit him with the bottle. It was awful. The blood sprayed all down my arm - it was covered."

A 25-year-old was arrested on suspicion of assault and is being held in custody at a south London police station, according to the Evening Standard.

The event was put on for journalists, PRs, celebrities including Tinchy Stryder, the casts of The Only Way Is Essex and Made in Chelsea. However, hundreds of competition winners also won tickets to the event.

Police reportedly stopped around 450 people from leaving the venue for up to two hours as they launched an investigation. The PC Advisor team was invited to the event but we're quite pleased we were unable to attend after hearing the news.

The shocking news has overshadowed RIM's launch of BlackBerry Mobile Fusion, a device management solution for enterprise customers. It provides features including support for multiple devices per user, application and software management and connectivity management.