A billing error which led to British Gas customers having their direct debit payments taken twice may have affected thousands of people, MoneySavingExpert.com has learned.

MSE has received multiple emails and tweets from concerned customers all reporting the same issue, which started yesterday but has now been fixed, according to British Gas.

One affected customer claims he's been left over £300 short as a result of the error.

British Gas, which is Britain's largest energy supplier and serves over 14 million customers, told MoneySavingExpert.com the problem had been caused by a technical issue.

It wouldn't tell us the precise number of customers affected, but said it was "less than 1%" of customers.

A spokesperson added: "We have resolved the issue, and have already refunded most customers. Any remaining customers affected will receive their refund by Monday at the latest.”

What are customers saying?

How can I get a refund?

British Gas told us it was proactively identifying and refunding affected customers even if they hadn't been in touch with the firm. But if you're concerned you may have been double-charged, it's worth checking your bank statement to see if there's a problem.

You can call British Gas' customer service team on 0800 048 0202.

If you switched to British Gas in our recent collective switch, you can contact the dedicated customer service team for our Big Switch Event 5 on 0800 975 9712, or email them at msecollectiveswitch@contactus.britishgas.co.uk.

If you've been double-charged because of today's error, you may also have incurred extra charges or expenses as a result.

For example, you may have been charged a fee if your bank account has gone overdrawn, or you might have been charged interest if you had to buy essentials on a credit card because you were out of funds.

If you have, make sure you keep proof of these, such as bank or credit card statements, receipts and screenshots. British Gas is advising customers seeking a refund of these charges to get in touch.

Have you been affected by this problem? Get in touch