TalkTalk customers are being warned about scammers who managed to steal account numbers, names and personal information from the company’s computers.

Broadband and phone operator TalkTalk emailed customers yesterday to tell them that it suffered a major data breach in which account numbers, addresses and phone numbers have fallen into the hands of fraudsters who have used the data to steal thousands of pounds.

The fraudsters used this personal information to cold call customers, in order to gain access to their computers and bank accounts.

The data breach was uncovered when TalkTalk investigated a sudden rise in complaints from customers about scam calls between October and December 2014 on its forums.

The email stated “Following a detailed investigation, we understand that some customer information, including account numbers, could have been illegally accessed in violation of our security procedures. No financial data was at risk as this is encrypted on our systems”.

“We have been working with an external specialist security company to take urgent and serious steps to prevent this happening again”.

One victim lost over £2,800

One customer, Graeme Smith, told the Guardian that he had fallen victim to one of these scammers and lost £2,815 after fraudsters phoned him and convinced him to install a piece of malware on his computer and pass over bank details. They were subsequently able to transfer cash to their own account.

Customers who have been caught out should contact their bank said TalkTalk, who have also set up a dedicated phone line for customers targeted by the scammers. Victims can call 0800 083 2710 in the UK to get help from the telecoms firm.