The Thomas the Tank Engine and Friends video which a Durban woman bought for her grandson proved to be steamy in more ways than one.

Thomas and Friends, Volume 9, began with the popular steam engine's adventures but 40 minutes into the video it went badly off the rails, the "friends" becoming hardcore porn stars.

Having seen the Thomas the Tank Engine series of videos advertised at R49,80 in Makro's glossy Christmas catalogue, Joyce Willnecker, bought the video and had put in on for her four-year-old grandson to watch when he suddenly asked: "Granny, what's happening?"

"To my horror the most raunchy sex scene filled the screen, complete with graphic close-up shots," she said.

"I was in such a state of shock,I was barely able to figure out how to switch it off!"

The video comprises 13 short stories and the explicit images cut into one appropriately titled Put Upon Percy, and continue for about half an hour. Featured, among other things, is a naked man with several obliging women.

"I was intending to keep the video as a Christmas present for my grandson," Willnecker said. "Thank heavens I didn't or it could have ruined our Christmas!"

Makro Springfield general manager Chris Jones said the store's entire stock of Thomas & Friends videos - all nine volumes - were removed from the shelves immediately the complaint was received.

"We will also alert all other Makro branches throughout the country which will, in turn, clear their shelves of the Thomas videos as well.

"Fortunately, due to the fact that all our shoppers are required to have store cards, we will be able to go to our database, identify every shopper who purchased one of the videos, and notify them of the problem to avoid any nasty surprises on Christmas morning," he said.

Makro staff watched several of the Thomas videos in stock on "fast forward" on Friday, but none featured the steamy scenes contained in Willnecker's copy.

Sonja Shear, general manager of Ster Kinekor Retail, which manufactured and distributed the video, said that until she had seen the video and investigated the matter she could not comment on how Thomas went off-track, or how many copies of videos containing the pornographic scenes were distributed.

"The video was made at our duplication plant in Johannesburg.

"As soon as I have the tape in my hands we will be able to obtain some clues from it and then conduct an investigation," she said.

The batch of Thomas the Tank Engine video tapes in question were supplied only to Makro stores.

Hugely popular with young children worldwide, the British-made television series is based on the Railway Series of stories by the Reverend W Awdry.