A renowned writer and illustrator of children’s books has suggested John Lewis may have plagiarised one of his stories for its latest Christmas advert, which was launched to great fanfare last week.

Chris Riddell, who until recently was the children’s laureate, posted his own version of the advert on social media, comparing it to scenes in his similarly themed book Mr Underbed. He posted: “John Lewis help themselves to my picture book.”

Like Moz, the huge, snoring, under-the-bed monster that features in the retailer’s campaign, Mr Underbed is a large but lovable furry monster, said Riddell, who is also a political cartoonist for the Observer.

“The idea of a monster under the bed is by no means new but the ad does seem to bear a close resemblance to my creation – a big blue unthreatening monster who rocks the bed and snores loudly,” he said. “Needless to say, I think Mr Underbed is a lot more appealing than Moz, but of course, I’m biased. I’ll be fascinated to hear John Lewis’ thoughts on the matter.”

Moz the monster was created by John Lewis’s long-term agency Adam&Eve.

The launch of the retailer’s Christmas advert has become an annual media moment. This year’s two-minute ad was made by the Oscar-winning screenwriter Michel Gondry, who directed Eternal Sunshine of the Spotless Mind. Such was the pre-launch secrecy that journalists wanting to view the advert first had to sign a legal non-disclosure agreement.

The campaign, which premiered on Channel 4 on Friday, is estimated to have set the retailer back £7m. The soundtrack features a classic Beatles song, Golden Slumbers, from the 1969 Abbey Road album, re-recorded by the rock band Elbow. By Thursday evening the ad had been watched almost 8 million times on YouTube.

Riddell said: “I was struck by the similarity of the concept when I watched the ad, and subsequently a number of people have tweeted and emailed me pointing this out. So I decided to do a Facebook post, tongue in cheek, about John Lewis promoting Mr Underbed.

“It was the first picturebook I wrote and illustrated and was published in 1986. Subsequently, at the publisher’s request, I re-illustrated it in 2009. During my time as children’s laureate I spoke about Mr Underbed often at public events, as my first book.”

Riddell has also authored Goth Girl and the Ghost of a Mouse, which won the Costa children’s book award, and has three times won the Cilip Kate Greenaway medal for distinguished illustration in a book for children. He was the ninth children’s laureate, serving from 2015 until 7 June this year.

It is not the first time the retailer has faced accusations over the inspiration for one of its festival ads. In 2014, similarities were pointed out between its campaign featuring a young boy and his sidekick Monty the Penguin and Oliver Jeffers’ 2005 children’s bestseller Lost and Found, although the author himself did not comment.

On that occasion, a John Lewis spokesman dismissed the claims, saying “stories about penguins at Christmas time are not new, and the story in our advert is totally unique”.

A John Lewis spokeswoman said: “The story of a big hairy monster under the bed which keeps a child from sleeping is a universal tale which has been told many times over many years.

“Ours is a Christmas story of friendship and fun between Joe and Moz The Monster, in which Joe receives a night light which helps him get a good night’s sleep. The main thrust of our story is utterly different to Chris Riddell’s.”