The old-fashioned wallet will be obsolete in the US within four years, an electronic payments company has claimed.

Scott Thompson, the president of PayPal, said: "We believe that by 2015 digital currency will be accepted everywhere in the US – from your local corner store to Walmart.

"We will no longer need to carry a wallet," said Mr Thompson, whose California-based company profits from customers switching from physical money to payments online and over mobile phone.

"Consumers are increasingly giving up traditional payment methods," including cash, cheques and even debit cards, Mr Thompson said.

Earlier this week Harrods became the latest major retailer to stop accepting cheques as payment.

Mr Thompson made the comments in a blog post to mark what the company claimed was its 100 millionth subscriber.

The company has launched a publicity campaign in which five people in San Francisco will attempt to pay for all their purchases with digital currency, despite the fact many shops still do not accept it.

PayPal has said it expects to process $3 billion (£1.9 billion) worth of payments over mobile phones this year.

(Read by Nelly Min. Nelly Min is a journalist at the China Daily Website.)