An IT expert is in a critical condition in hospital after he was stabbed in an apparently unprovoked attack while walking alongside the River Thames, police said.
The 41-year-old Canadian man, from Southwark, south London, was walking along Bankside, close to Southwark Bridge and the Anchor Bankside pub, when he was stabbed in the chest between 12am and 12.10am on Friday.
The man, who was carrying a skateboard at the time, was taken to an east London hospital where he is in a critical but stable condition.
Detectives from Southwark are investigating but there was no apparent motive for the stabbing, the Met Police said.
There have been no arrests but the suspect has been described as a male, approximately six-feet tall and wearing a dark or grey hooded top.
Detective Sergeant Nick Blackburn, of Southwark CID, said: "This was a seemingly unprovoked and callous attack, and we are obviously extremely keen to speak with anyone who might have information that could help us to identify the culprit.
"Were you in or around that area at that time? Or did you see anyone in that area acting suspiciously? If you believe you might be able to contribute to this investigation in any way, please do give us a call."
Witnesses or anyone with any information should call police on 101 or 020 7232 6202 or Crimestoppers on 0800 555 111.