A murder investigation has been launched after a man who was beaten in a "mindless" attack in Trafalgar Square died from his injuries six months later.
Desmond O'Beirne, 51, was attacked by two men outside the National Gallery at around 00:25am on 3 June 2017.
CCTV images show one of the suspects hitting O'Beirne around the head before a second kicks him while he's on the ground. The victim was taken to hospital but he eventually died from his injuries on 20 December 2017.
A post-mortem examination ruled the 51-year-old died as a result of head injuries.
Police have issued images of two men they want to speak to in connection with the attack. Officers also believe the suspects may have "boasted" about attacking the victim to friends and family.
The first suspect is described as having a top knot hair style, full beard, red t-shirt, dark trousers and light colour shoes. Suspect 1 can be seen to punch to the back of the victim's head.
Suspect number two was wearing a black jacket with a white emblem on right shoulder and white writing with a picture on the rear. He was also wearing a white top under the jacket, dark trousers and dark shoes with white soles.
Detective chief inspector McHugh said: "These two men will have spoken to friends and partners and possibly boasted about their mindless attack. I want you to call us with their names.
"The males are distinctive and will be known to their group that evening. Desmond never regained consciousness after the brutal attack and it is vital we bring his attackers to justice."
"Officers are keen to trace anyone who was in the area at around this time and witnessed the incident, particularly anyone who filmed or took photos of the attack, or the events either side of the attack.
Anyone with information is asked to contact the incident room on 020 8785 8099. To give information anonymously call Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.