A campaign by the mother of a ten-year-old boy who suffered an epileptic fit triggered by a computer game has persuaded a leading manufacturer to change how it vets its products.

When Gaye Herford heard her son screaming in his bedroom, she rushed in and found him rigid and twitching uncontrollably. Tests revealed that the fit, diagnosed as photosensitive epilepsy, had been caused by flashing lights on his Nintendo game console.

Mrs Herford won the backing of dozens of MPs who signed an early day motion in the House of Commons calling on manufacturers to screen games for characteristics that could induce fits. She has even persuaded Ubisoft, one of the world’s largest manufacturers of computer games, to vet all its products.

Television and cinema films are already statutorily tested. If the law is changed, Britain will have the world’s toughest controls on computer games.

Mrs Herford, 45, a dentist from Winscombe, Somerset, said: “Most people don’t know if they’re susceptible to epilepsy caused by flashing lights. We need a change in the law to force all game manufacturers to remove the scenes that can provoke epileptic fits.

“Parents should know that every time they buy their child a game, there is the potential for an epileptic fit unless we make safety-testing law.”

Her son was playing Rayman Raving Rabbids when the attack occurred, in May. She said: “As I held him he was rigid. His look was blank. I could see the side of his face and his left hand twitching and he told me, ‘Mummy, stop these lights and flashes please’.”

Latent photosensitive epilepsy, which was revealed by electro-encephalograms at Bristol Children’s Hospital, is most common in those aged between 7 and 19, the group that plays the most video games. The fits are usually triggered by particular patterns of flashing light or intense shades of red.

In June a short animated film introducing the 2012 Olympics logo was inadvertently broadcast on television without being tested and was said to have caused dozens of epileptic fits.

John Penrose, the Conservative MP for Weston-super-Mare, who tabled the motion, said: “We don’t allow toy-makers to sell products that could poison or injure our children. This shouldn’t be any different. We need government action, now, to change the law so no more young lives are affected by seizures triggered by electronic video games.”

The campaign is being backed by Graham Harding, an authority on photosensitive epilepsy. He developed the Harding flash and pattern analyser, which the Independent Television Commission adopted in 1994 and which is still the standard test to guard against epilepsy-inducing scenes.

Professor Harding said: “We don’t want a war with manufacturers, just for them to be sensible and comply.”

Rob Cooper, managing director of Ubisoft UK, said: “Our immediate response to Gaye Herford was to not just take note but to take up her case. Testing of the original Rayman Raving Rabbids Nintendo DS game showed that no images posed a high risk for photosensitivity epilepsy.

“However, we took the view that different people can react in different ways and made a decision to prescreen and pretest all Ubisoft in-house developed games regardless of platform, prior to publication.”

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