Around 18,000 people were charged twice for their BT Internet services this month, following a billing error at the dominant fixed-line telco.

According to a BT spokesman, only a tiny percentage of the company's dial-up and broadband customers were hit by the snag.

In an email to punters BT apologised for the mistake explaining that an error in its billing systems "may have caused your November Direct Debit to be collected from your bank account twice".

BT is to give customers a full refund. ®