Callum Smith's opponent Lenin Castillo was taken out of the ring on a stretcher after being knocked out in the second.
Back in the ring for the first time since his defeat to Canelo Alvarez in December, Smith's introduction to light-heavyweight level began with some decent hits and a flurry of jabs in the first round, with Castillo trying to replicate and making contact with a number of body shots.
In the second though, a huge hit from Smith was decisive and left Castillo lying on his back, with the referee quickly calling the bout.
Smith was making his light-heavyweight debut on the undercard of Anthony Joshua's clash with Oleksandr Usyk.
In what was a scary scene, Castillo appeared to twitch on the canvas and was then given lengthy medical treatment.
He has now been escorted out of the ring and is said to be on his way to a local hospital.
We will bring you further medical updates once we hear anything further.
