UK banking group Barclays has made a change to its terms and conditions that will allow it to resell anonymous, aggregated customer data to third parties. 

The banks says that from October, it will offer third parties access to aggregated data to provide insights into its customers' spending habits. 

“We can combine information about you with information about other Barclays customers to create reports which we may share with companies outside Barclays,” the bank told its customers. "This information is numerical and not personal, and you will never be identifiable on the basis of it."

Further details of how the information will be used has not been revealed, but Barclays have said it will also be using customer transaction data internally to “increase our understanding of services and products that you may wish to use.”

It will also start tracking customers through mobile phones and social media to help detect fraud.

The bank will not need consent from customers and they will be unable to opt out of the scheme, but Barclays insists it is acting in accordance with the Data Protection Act.

Barclays is just one of many firms to harvest new revenue streams from selling on data about its customers. 

Earlier this month, telcoms Vodafone, O2 and EE stirred controversy after announcing a joint scheme to sell on aggregated information about its customers to sell advertising online.