Mild winters are thought to have led to an increase in exotic spider numbers
A grandmother spent more than 24 hours on a life support machine after being bitten by a spider.
Lyn Mitchell woke up struggling for breath when she was bitten on the chest while in bed at her home in Cumbria.
The spider, later killed by pest control experts, was a false black widow, which usually causes blistering.
It is thought Mrs Mitchell, 52, of Egremont, suffered an allergic reaction and that the spider was attracted by the warmth of her electric blanket.
She was taken to the West Cumberland Hospital in Whitehaven in the early hours of 3 January and spent 26 hours in intensive care.
Experts say false widow spiders are not usually aggressive, but can deliver a bite when they are unintentionally touched.
Mrs Mitchell said: "For 26 hours I was on life support.
"I saw the spider run all the way along the bed. But it was so quick, I've never seen anything run so quick in my life.
Lyn Mitchell said she felt ill after being bitten
"I was so poorly and I just got the phone and called the doctor because I looked down and realised I had been bitten.
"By the time my daughter got to the hospital, which was only two minutes, they had put me on the life support machine because they couldn't wait.
"Since I was a child I've always picked spiders up and put them outside. But now I'd just squish it first."
Pest control officers from Copeland Council sprayed her home and Mrs Mitchell found the spider dead behind her bedroom door several days later.
She said the Natural History Museum told her it was the worst case of its kind they had come across.
The false widow - Steatoda grossa - is purple and black in colour and up to 0.4in (10mm) in length and resembles the deadly black widow.