The 21 inch television sets should have been priced at £299.99 - but were offered at the bargain price after that figure was rounded up to £300 and the two noughts left off by mistake.

The BBC's Chris Nuttall: "It is thought that it could cost Argos up to £1 million"

Word spread quickly with many customers placing multiple orders.

By the time Argos discovered the mistake there were reported to have been hundreds of orders worth more than £1m. One person was reported to have ordered 1,700 sets.

Test case

The retailer has decided to refuse to honour any of the orders placed for the £3 Sony Nicam sets - a decision which could lead to a legal test case on Internet trading.

Argos said it had consulted its lawyers and the Advertising Standards Authority before deciding not to honour the contract.

A spokesman added that because it had not confirmed that any of the orders had been accepted, no contract existed to sell the TV sets at the £3 price.

Terry Duddy, Argos chief executive, said: "We have a great Internet site that now gets over 100,000 hits per month.

"It has some tremendous offers on it but clearly a TV for £3 is not one of them.

"This was obviously an error we rectified very quickly. We shall be contacting each customer directly to apologise, explaining their orders cannot be accepted in this case."