This heart-stopping video captures the moment a gas engineer is confronted by a huge spider - the size of a mouse.
John Buchan, 24, discovered the 10cm-long arachnid - which he believed to be a freakishly large false widow spider - lurking in a metre box.
A petrifying clip, shakily recorded on his mobile phone, shows the spider scuttling around a web.
The father-of-one, from Niddrie, Edinburgh, said: “I opened up the external gas meter and didn’t notice the spider straight away.
“Then I spotted it. It was about the size of a mouse - even bigger.
“I see spiders all the time doing this job by I have never seen anything like that.
“It’s body was enormous - it had a big ball on it’s back.
“It’s legs were thicker than anything I’ve ever seen - they were hairy and horrible.
“From its bottom legs to the top it was probably about 10cm long. It was about the size of a can of drink.
“It was moving around a lot. I touched it with something and it started running. It was moving quickly around the metre box.
“I showed the tenant a photo of it and he said, ‘I hope it doesn’t get in here’.”
False widow spiders, which usually grow to the size of a 20p coin, have dark, shiny bodies with pale markings.
They pack a poisonous, painful bite which can trigger serious allergic reactions causing chest pain, swelling and nausea.
But Professor Adam Hart, of the University of Gloucestershire, said the spider is probably an oversized house spider.
He said: “We usually see large numbers of them in the autumn as the males move around looking for mates - this tends to being them into our houses.
“Some of them can be pretty impressive but they aren’t dangerous.
“We have a very benign fauna in this country - there are very few things that can do us any harm at all and even the larger spiders are basically harmless.”