After a trip from Aldi, the last thing you expect is to be attacked by a snake lured by the chicken in your shopping bag. But this is exactly what happened to poor Patricia Bullock.

The mother-of-two was walking past a hedge along Lansdowne Crescent in Worcester like any other normal Sunday afternoon when the reptile appeared out of nowhere and bit her leg.

"It was as quick as anything," said Bullock, 57. "As it lashed out, it hit the carrier bag to get the chicken, but it got my leg instead – I was absolutely shocked. The pain was like having a glass cut and my leg started to burn like it was on fire."

Bullock managed to hobble home and treat her leg wound.

"I sat down and I pushed the edges of the red ring and I squeezed out most of the poison until it started to bleed. That's when I noticed the two marks from the snake's teeth.

"For the first few days, I was in shock more than anything. I was shaken and nauseous.

"I can't sleep at night because I have visions that the snake is going to lash out at me."

Nigel Hands, a snake expert, said it was unlikely there were adders – the only venomous snake native to the British Isles – slithering around the area, and said the snake was more likely a pet that had escaped from its owner's home.

"In urban areas occasionally grass snakes turn up in gardens, but adders are very choosy about their locations," he said. "I think someone may well have lost a pet, but snakes aren't out to hurt people, it was most likely frightened."

Mark Cox, from Worcestershire Regulatory Services, said: "We licence people who keep dangerous and wild animals and don't know of anyone who was lost a pet, if they did, they would lose their licence."

As the mystery of the snake remains unsolved, Bullock will walk next time across the other side of the road.