The 22-year-old victim had been on his way home from the town when he was approached by a group of four men in Kent Road at around 3am on Sunday 11 June 2023.
The suspects, who are unknown to the victim, are reported to have assaulted him in an unprovoked attack. The victim was punched in his face multiple times and hit to the back of the head with what was believed to be a gas canister.
He was taken to a London hospital where he remains in a serious condition.
Following the incident officers carried out enquiries and arrested two people.
Investigators are now appealing for witnesses to assist with identifying two other suspects.
The suspects have been described as two white men who were both wearing dark tracksuit bottoms.
One man was wearing a dark-coloured coat with a hood up and white trainers. The second man was wearing a black hat with a yellow and red logo, a black jacket and a white t-shirt.
Anyone with information should call the North Kent appeal line on 01474 366149, quoting crime reference 46/103307/23.
You can also contact Crimestoppers anonymously on 0800 555111 or by using the online form on their website.
