The UK government is secretly planning to force technology companies to build backdoors into their products, to enable intelligence agencies to read people’s private messages.

A draft document leaked by the Open Rights Group details extreme new surveillance proposals, which would enable government agencies to spy on one in 10,000 citizens – around 6,500 people – at any one time.

The document, which follows the controversial Investigatory Powers Act, reveals government plans to force mobile operators and internet service providers to provide real-time communications of customers to the government “in an intelligible form”, and within one working day.

This would effectively ban encryption, an important security measure used by a wide range of companies, including WhatsApp and major banks, to keep people’s private data private and to protect them from hackers and cyber criminals.

Amber Rudd caused uproar in March when she called for WhatsApp to allow government agencies to read encrypted messages.

The service scrambles data so heavily that it can’t be deciphered by anyone other than the sender and the recipient and, crucially, not even WhatsApp can read the messages sent through its app.

Apple CEO Tim Cook once branded backdoors as “the software equivalent of cancer”. Even if the government has good intentions, backdoors expose everyone to cyber criminals too.

Approval from a judge appointed by the Prime Minister would be required before an individual could be targeted by government agencies, and the proposals outlined in the document also need to be approved by both Houses of Parliament before passing into law.

What is perhaps most alarming, however, is the lack of transparency around the draft powers.

The proposals are currently only being discussed with members of the UK’s Technical Advisory Board, which are BSkyB, BT, Cable and Wireless, O2, Virgin Media and Vodafone, as well as representatives from government agencies, believed to include GCHQ and MI5.

The short, four-week consultation ends on 19 May, and the document isn’t available to access through the government’s website.