A Scotsman credited with inventing the world's first automatic cash machine has died at the age of 84 after a short illness, his funeral director has said.
John Shepherd-Barron died peacefully in hospital in Inverness, northern Scotland, on Saturday, said funeral director Alasdair Rhind.
He started thinking about how to obtain cash outside business hours after being locked out of his bank, and the eureka moment came when he was in the bath, the BBC reported.
"It struck me there must be a way I could get my own money, anywhere in the world or the UK," he told the broadcaster in a 2007 interview.
"I hit upon the idea of a chocolate bar dispenser, but replacing chocolate with cash."
Barclays commissioned the invention and the first automatic teller machine (ATM) was installed at a London bank in 1967. It paid out a maximum of 10 pounds a time.
Plastic bank cards had not been invented at the time, so Shepherd-Barron's machine used cheques impregnated with carbon 14, a slightly radioactive substance, according to reports.
After detecting it, the cheque was matched against a PIN (personal identification number).
The inventor played down the health concerns surrounding the radioactive cheques, saying in 2007: "I later worked out you would have to eat 136,000 such cheques for it to have any effect on you."
He had originally wanted a PIN number to comprise six digits but his wife told him she would only be able to remember four.
"Over the kitchen table, she said she would only remember four figures, so because of her, four figures became the world standard," he said.
There are now more than 1.7 million automatic cash machines worldwide, according to the ATM Industry Association.
Explore further: Reflected smartphone transmissions enable gesture control