Officials fear it was a “copycat” incident after four kittens were abandoned in the same place last year.
He makes his way to the men’s loos before emerging moments later without the bag. He appears to rush back through pub before leaving.
Hours later, on Friday 28 June, a staff member discovered the bag with four frightened kittens in, three female and one male.
The RSPCA, which took the animals in, said the kittens were too young to be away from their mother, and their lives were at risk.
Inspector Deborah Scotcher, who is investigating, said: “The man can be seen entering The Ritz pub with his hood up, carrying a bag that bears a striking resemblance to the bag the kittens were found in.
“These kittens were far too young to be away from their mum, and it was touch-and-go as to whether they’d survive.
“But I’m really pleased that they all pulled through thanks to the dedication of our fosterer who hand-reared them and fed them round the clock.”
She added: “We believe this man can help with our investigation so we’d urge him – or anyone who recognises him – to get in touch with us.”
Four kittens were also found in a bag in the pub’s loos last March.