The Government is planning to force social media and internet companies to break encryption to help spies monitor communications, a leaked report has revealed.

In an extension of the security agencies' abilities under the Investigatory Powers Act, the Government could force companies to change their technology so they can comply with warrants.

The secret document, which was only shared with a handful of communications companies, was revealed by privacy advocates the Open Rights Group. The organisation said it could mean encrypted messaging apps such as WhatsApp having to limit encryption.