A bite from the Brazilian Wandering Spider can cause painful erections lasting for hours.
The Brazilian Wandering Spider is the world's most venomous arachnid Wikipedia

UPDATE at 18:00 on January 22: The RSPCA believes the initial identification of the unusual spider as a Brazilian wandering spider was incorrect. The spider is now being cared for by a specialist until its identification is confirmed, after which a suitable home can be found for it.

A supermarket customer was shocked after he found the world's deadliest spider in a bunch of bananas he had purchased for lunch.

Neil Langley, 52, an admin worker at the Department of Work of Pensions, bought the bananas from Asda, in Tipton, West Midlands, but did not notice the Brazilian Wandering Spider hiding in between the bananas.

Langley didn't notice the brown eight-legged intruder until he got to his office, the Mirror reported.

He said: "I bought a bunch of four or five bananas at the Asda and put them in a bag but I didn't notice the spider until I was at my desk the next day.

"It was in one of the clear bags you use for fruit and it must have just woken up.

"I was lucky it hadn't crawled out at home or in my work bag."

As soon as Langley saw the spider, he and his colleagues called the RSPCA.

"I first saw something moving out of the corner of my eye and it wasn't a normal grey spider you get in this country, it was quite big. I put it in a plastic bag and had a big discussion with my colleagues about what to do with it. We even discussed flushing it down the toilet!

"Eventually a colleague who is an animal lover put it in a cereal box and gave it to the RSPCA, who took it away. It must have made a difference to the cats and dogs they usually get called out to."

The spider was collected and transported to a new home in Bristol Zoo.

Langley thinks it's not the fault of Asda and that the spider was accidentally packaged.

"The bananas are imported from places like Costa Rica and South America and the supermarkets buy them from wholesalers. I told the manager at the store and he promised to look into it.

"I'm going to keep on buying bananas for my lunch but I'll be a bit more circumspect when I get six or seven together."

The critters are considered to be the world's most venomous spider, whose bite can cause painful erections that last for hours. Their bite can also cause cramps, hypothermia, vertigo, blurred vision, intense sweating and convulsions and a person can die within hours of being bitten.

In an interview with the Daily Express, Asda said in the past: "We sell sound one billion bananas every tear and each and every one is washed, sprayed and manually checked for quality and stowaway before being transported to the UK.

"We'd like to reassure all our customers that the chance of finding a spider is incredible low and it's even less likely that a tropical spider could survive outside of their warm climate."