A dad was left in agony as his limbs "exploded" after he was savaged in the night by Britain's most dangerous spider. Brian Smith had woken up in bed to a sharp pain on the top of his right hand but went back to sleep because he thought he was dreaming.

It was only when the 43-year-old spotted two small fang marks the next morning that he became increasingly concerned as he began to struggle moving his hand. Mr Smith was rushed to hospital by ambulance and photos from his bed show his arm, leg and foot all increased in size massively as venom from the bite ran rampant through his body. It's thought Mr Smith was bitten by a false widow spider. The bites are usually mild, similar to a wasp sting. However in rare cases, hospital treatment can be needed if symptoms get worse or there is an allergic reaction.

In his case, Mr Smith said doctors told him his hand could only swell 20% more before "exploding". He was hospitalised for three weeks and the venom spread from his hand to his shoulders and left leg.

At one stage the dad-of-three's leg ballooned so much that the scaffolder was forced to use crutches for weeks and he's still suffering with a limp, an aching hand and arthritis symptoms.

Now Mr Smith checks his bedsheets for any pesky creatures and is warning others to remain vigilant of venomous spiders too.

Mr Smith, from Maidstone, Kent, said: "I was quite shocked a spider in the UK could cause this sort of damage. I thought this only happened in Australia and places like that.

"It wasn't until I looked properly at my hand that I saw two little prick marks where its two fangs must've gone in and bit me.

"I couldn't do anything with my hands, the pain was too much. It was a sharp pain and was getting worse and worse through the day."

Doctors told Mr Smith he had suffered a serious reaction to the spider's venom and may need a portion of his hand cut off.

He added: "[The doctors] told me I had 20% left of my hand to swell before it would explode like a balloon.

"The skin was going to explode due to the pressure so I would've needed a skin graft. Thank god I didn't lose my hand. The poison must've reacted with my blood. It was so swollen and my hand kept changing colours from purple to red.

"I don't know any other spider in this country aside from a false widow that can cause this sort of damage.

"My immune system started attacking different parts of my body and I've now got reactive arthritis because of it and I'm on steroids for three months."

After three weeks in hospital, Mr Smith finally began responding to medication and was discharged to return home where he's cautious about what could be sharing his bed.

He said: "I'm slowly getting better but I'm still not 100%."

According to the Natural History Museum, false widow spiders, species in the genus Steatoda, are sometimes confused for the more deadly black widow spiders, which are not native to the UK. Both groups of spiders have a similar dark-coloured, globular body.

Species

Six false widow species live permanently in the UK. The three most common false widows are; the rabbit hutch spider, Steatoda bipunctata, the cupboard spider, Steatoda grossa, and the noble false widow, Steatoda nobilis.

Size

Females are larger than males, with the largest species (noble false widow) measuring around 8.5-14mm, with males 7-10 mm.

Identification

All species have distinctive sets of markings on their abdomens (the rear part of the spider's body). They have a narrow white or lighter band around the front of the abdomen towards their head, with other markings that vary by species.

However, all of these markings can be variable, faded, or missing, especially in adult females. Females have globular, shiny abdomens. Male abdomens are smaller and less rounded, but have clearer markings.

Their webs are a tangle of criss-cross threads which may become quite dense in the centre if left undisturbed.

Bites

Although false widows do have a venomous bite, the venom is not particularly potent. Usually the only symptom is pain at the site which may radiate away from the bite. It ordinarily lasts between one and 12 hours, and rarely for more than 24 hours.

Often, the symptoms are no worse than the pain of a wasp sting. Males are more prone to biting. But this is only because they leave the nest in search of a mate, often venturing indoors looking for females. They are only known to bite when provoked or trapped against skin.

Pest control

Jan Beccaloni, Curator of Arachnida and Myriapoda from the Natural History Museum, said: "During my time at the Natural History Museum I have, not surprisingly, met many people who are scared of spiders. That’s a great pity because spiders are awesome creatures which are sadly misunderstood.'

"Aside from their key role in feeding on pest insect species, their silk is being developed to make specialist clothing such as bullet-proof vests and their venom can be used in pain relief.'

"So next time you find an unwanted spider in your house, please don’t kill it! Either leave it in peace, or humanely put it out in your shed."

False widows can live in relative harmony with us - they're even tidy houseguests, helping to keep our homes clear of flying insects and other pesky invertebrates.