When British inventor John Shepherd-Barron applied his mind to finding an easier way to access money while traveling, he likely did not predict how universally his idea would be accepted.

He looked at the ubiquitous chocolate bar dispenser found at railway stations throughout the United Kingdom, and reasoned that the same delivery method could be adapted to issue money.

His idea resulted in the first ATM, or automated teller machine, being unveiled on June 27, 1967, outside a branch of Barclays Bank in Enfield, North London.

Fifty years later, there are 3 million ATMs worldwide - with China home to almost 50 percent of them, according to World Bank statistics. Self-service cash machines are used for around 8.6 billion withdrawals a year.

By using either a debit or credit card, bank account holders can use a simple pin code to withdraw cash, or check balances, anywhere in the world, avoiding the need to join a queue at a counter.

Shepherd-Barron, who died in 2010, once told an interviewer: "It struck me there must be a way I could get my own money, anywhere in the world, or the UK. I hit upon the idea of a chocolate bar dispenser, but replacing chocolate with cash."

He struck a deal with Barclays, signing the contracts in typically British fashion, over a pink gin.

To mark the golden anniversary of the first ATM, Barclays has painted gold the modern day Enfield cash machine.

Although ATMs remain popular - and convenient - the use of cash is declining in many areas, according to Bank of England Chief Cashier Victoria Cleland.

She told the BBC that 94 percent of British adults use cash machines, with cash accounting for almost half of transactions. But changes in financial activities in countries including Sweden and China may mean cash machines have reached their peak. Both countries are known for their increasing use of electronic transactions - in which the buyer simply presents a smart phone code to a scanner at a point of sale. Systems in use include AliPay, WeChat, and Apple Pay.

Sweden now has the lowest proportion of cash machines in Western Europe, with 333 per one million inhabitants. Portugal, on the other hand, has 1,516 per million people.

ATM manufacturer NCR said it is now trying to make the machine a "bank branch in a box" after research showed 80 percent of transactions across the counter could be handled by a video teller on such a device. It's already a common scene in China Merchants Bank branches all over the Chinese mainland.