A “plump” duck has been rescued after being left on a train at Herne Hill Station in London.

The duck, named Jack by a rescuer, was found by a passenger on Friday evening as Southeastern railway alerted travellers to the incident on Twitter and requested its owner “please make yourself known” to station staff.

The duck’s saviour, Ann Aitken-Davies from London Wildlife Protection, said she named the bird Jack after the baby found in a handbag on a train station in The Importance of Being Ernest.

“Jack was in a nappy and squashed into a bag,” she told the PA news agency.

“He is plump and in very good condition.

“I have no idea why he was dumped but his owner knew he would be found if left on a train.”

Jack remains with a Swan Sanctuary volunteer and will be given a permanent home there after a period of quarantine.

Southeastern tweeted that Jack is believed to be a pet and thanked Twitter users for “all for your concerns for its welfare (and, of course, your quacking puns!)”

“Hope it hasn’t missed the last train – otherwise it will have to get up at the quack of dawn to get the next one,” one person responded.