Privacy groups the Open Rights Group, Privacy International and Big Brother Watch have written to internet service providers (ISPs), demanding that they stand up for their customers against the government' 'Snoopers' Charter'.

In an open letter, to Virgin Media, Sky, TalkTalk, BT, Royal Mail, o2 and Zen Internet, they are urged them to "withdraw their participation in a process" that they say "is deeply flawed, pursuing a pre-determined solution that puts competition, security and privacy at risk in an unprecedented way".

Signed by Jim Killock, executive director of the Open Rights Group, Big Brother Watch director Nick Pickles and Sam Smith, technologist at Privacy International, the letter calls on the ISPs to stop holding closed meetings with the government, saying that it "may end up with them becoming an arm of government law enforcement".

The letter reads: “It has become clear that a critical component of the Communications Data Bill is that UK communication service providers will be required by law to create data they currently do not have any business purpose for, and store it for a period of 12 months.

“Plainly, this crosses a line no democratic country has yet crossed – paying private companies to record what their customers are doing solely for the purposes of the state. These proposals are not fit for purpose, which possibly explains why the Home Office is so keen to ensure they are not aired publicly.”

Stating the privacy and security concerns of consumers, the letter says that the ISP's customers have not had the opportunity to comment on these proposals, and that this is a critical failure not only of the government, but is "a betrayal of your customers' interests".

“You appear to be engaged in a conspiracy of silence with the Home Office, the only concern being whether or not you will be able to recover your costs,” they said.

The Communications Data Bill is proposed to collect personal communications data, such as phone calls, emails and text messages. Home secretary Theresa May MP said that it will only be accessed by senior police and not held by the government, while critics have said that it is a "serious problem that requires action" and it has been called a "honeypot for hackers".

The bill was detailed in the last Queen's Speech at the state opening of Parliament in May 2012.