A creepy TV advert forces one horrified Swindon woman to look away whenever it appears on-screen.

The short clip spreading awareness of Tesco’s offer to reduce prices for Clubcard members has popped up regularly in ad breaks and has been met with alarm by some viewers.

In the advert, a woman at the tills in one of the supermarket’s stores notices that the prices for her pizza, fish fingers, fries, and chicken nuggets are lower than usual.

When the shopper scans her Clubcard app, which brings the total down from £17.30 to £10, the camera looks closely at her face transforming into a bizarre exaggerated grin and Snap’s I’ve Got the Power starts playing.

The effect distorts the customer's face as she leaves the shop and walks home, with other Tesco customers that she passes on the way having the same rictus grin and cartoonish eyes.

The ad ends with her at home, picking up a biscuit while staring directly into the camera. The biscuit breaks in half and one piece lands near her dog – whose own visage transforms into the broad toothy smile and oversized eyes.

Patricia Smith called the Adver to complain about the advert, describing how it causes her distress as soon as it starts playing.

She said: “I’m not usually affected by this stuff, but I think the advert is disgusting.

“That smile is so eerie and horrible, I can’t look at it, it's a scary thing to see on TV and it's on all the time.

"Something should be done about it, it should be taken off air. Surely, I’m not the only person has been upset by this.”

She certainly is not. The commercial by BBH London has been airing since mid-March and prompted dozens of complaints to the Advertising Standards Authority.

Viewers have been Tweeting about their distaste for the loyalty card campaign as recently as Thursday evening.

One user wrote: “The Tesco Clubcard advert becomes pure nightmare fuel because she saved a quid needs to die in a fire.”

Another added: “Oh no, it’s back, that awful Tesco advert with the woman turning into weird cartoon style horror, NO…”

A third said: “Pretty sure I’ll be seeing the Tesco advert in my nightmares at this point.”

Despite this backlash, Tesco is continuing to air the advert.

The retail giant has not yet commented publicly on the discomfort it appears to be causing.