Electricals retailer Comet faces an investigation by the data protection watchdog after it accidentally sold a TV set on its website for 2p, and then revealed the email addresses of more than 500 people who took advantage of the bargain when it wrote to them to say it would not be honouring the sale price.

The problem began when the Comet website offered the LG32LD450 TV set for only 2p, instead of the usual price of about £350. Hundreds of customers spotted the error and ordered the TV.

Comet then contacted the customers to say that, per the terms and conditions on its website, it would not process the orders. In the email, it blamed the mistake on a “computer error affecting our website”.

Instead of sending the email to customers using the BCC box, the email addresses - about 560 - were visible to all recipients, in contravention of the Data Protection Act.

A spokesperson for the Information Commissioner’s Office (ICO) said: “We have recently been informed of a possible breach of the Data Protection Act. The ICO is currently making enquiries into the circumstances of the alleged breach before deciding what action, if any, is required.”

Having already apologised to customers by email, Comet reiterated that it was sorry for the mistake, but that it won’t be fulfilling the orders.

A spokeswoman for Comet said: “This was a very unfortunate human error and we would like to sincerely apologise to those customers affected. Comet takes this issue very seriously and we will ensure all our customer service staff are reminded of our data protection obligations and procedures.”