A blind stroke victim said he thought he was going to die when he was shot in the back with a 50,000-volt Taser stun gun by a police officer who mistook his white stick for a Samurai sword.
Colin Farmer, 61, collapsed to the ground in shock and believed he was having another stroke which could prove fatal.
The police blunder happened as reports were received of a man walking through the town centre of Chorley, Lancashire, with the martial arts weapon.
Meanwhile, Mr Farmer, who has suffered two strokes and walks at a "snail's pace", was on his way to the pub to meet friends for a drink and did not realise anything was afoot.
Mr Farmer said he heard shouting on the street but did not know what it was about and thought he was going to be attacked by "some hooligans".
He was then struck by the Taser and fell to the ground in Peter Street, and dropped his white stick on the floor, before a policeman handcuffed him.
When the mistake was realised he was taken to Chorley Hospital for treatment and was later released. The incident happened at about 5.45pm last Friday.
Speaking to ITV Granada Reports, he said: "I was just walking along and I just heard some men shouting really angrily and I thought I'm going to get mugged. So I didn't know any police were here. The Taser hit me in the back and it started sending all these thousands of volts through me and I was terrified. I mean I had two strokes already caused by stress. When these volts were going through me I dropped the stick involuntarily and I collapsed on the floor face down."
He added: "I was shaking and I thought 'I'm going to have another stroke any second and this one is going to kill me. I'm being killed. I'm being killed'."
Lancashire Police apologised to Mr Farmer for the "traumatic experience" but confirmed the officer who fired the Taser has not been suspended and remains on duty. Mr Farmer says he is taking legal action against the force and wants the officer involved charged with assault.