A man suffered a collapsed lung after being repeatedly stabbed in an attack in Paddington.
The 27-year-old victim was found with multiple knife wounds in a flat in Woodchester Square near Warwick Avenue on Friday, April 21.
Police had been called to reports of a fight at 4.20pm but when they arrived no one was there.
Paramedics later told them they had been called to a nearby flat where they found a man seriously wounded.
Detectives are now appealing for the public's help to find out what happened during the stabbing.
DC Darren Barclay said: "This was a violent attack which left the victim with serious injuries.
“This happened in broad daylight in an area overlooked by residents, and we would urge anyone who saw what happened, or saw possible suspects in the area at the time, to contact police.
The stab victim was taken to a central London hospital to be treated and has since been discharged.
Two men were arrested on suspicion of attempted murder.
One man, aged 23, was arrested on Monday, April 24 and bailed until a date in mid-May while the other man, 25, has been released under investigation.
Witnesses and anyone with information is asked to call 020 7321 7647, or Crimestoppers on 0800 555 111 if you would prefer not to give your name.
