A couple of startled newcomers to internet banking have proved that honesty remains the best policy in the IT age, after an office glitch mistakenly credited them with £689,000.

Pausing briefly to wonder if the money was the ultimate tempter for new customers, the pair rang the online financiers Egg to ask what was going on.

"We kept getting messages on our computer saying that all these funds were available," said Jackie Tudor, 51, who works in a Cornish gift shop while her husband Steve, 46, skippers a transatlantic merchant ship. "We knew it wasn't our money because we'd only just started the account three days earlier with one deposit of £100."

The couple have been rewarded with the gift from Egg of the £1,034 interest the money earned while in their account - 10 days because of unspecified problems at the bank. The Tudors contacted Egg straightaway, but it took a further six days before the huge balance was downloaded to its rightful owner.

"We knew we could have a lot of fun with the money but we also knew that would be fraud," said Mrs Tudor, of Looe, who started the account with her husband to try a bit of dabbling in stocks and shares. "Steve is in the States at the moment and so if he had wanted he could have changed his name and run off with the money and we could have done well for ourselves - until we got caught.

"It was fantastic to have so much money in the bank but in the end honesty is the best policy."

A spokesman for Egg said: "A mistake was made on Captain Tudor's account which has been rectified."

The bank did not specify the cause of the bungle, beyond "a clerical error".