Nothing to worry the "law-abiding", American and British politicians have assured us, in the wake of the revelations of mushrooming mass US surveillance of phone, email and internet traffic. The electronic harvesting is in fact "very narrowly circumscribed", Barack Obama insisted. The behaviour of Britain's intelligence services was, David Cameron declared, entirely "proper and fitting".

In fact, courtesy of the whistleblower Edward Snowden, we now know the US National Security Agency is collecting 200 billion pieces of intelligence a month, hoovering up the mobile records of more than 200 million Americans and helping itself to a vast quantity of emails, web searches and live chats from the world's largest internet companies via a program called Prism.

Naturally, the NSA has been sharing some of its spying catches about UK citizens with its friends at GCHQ(the General communications headquarters), sparing the British authorities the tiresome need to arrange a warrant. But it was still authorised, the foreign secretary told parliament, apparently by himself. So nothing to fear there either.

Rampant blanket surveillance

Such rampant blanket surveillance of course makes a mockery of the right to privacy – guaranteed by the US constitution's fourth amendment – and that has been the focus of debate since the Guardian began publishing the leaks. However law-abiding a citizen, the dangers of manipulated phone or web "metadata" wrongly branding someone are legion and well-documented. And while interception of letters is an ancient intelligence practice, Prism is the equivalent of all letters being opened, copied and stored – in case they might be incriminating at a later date.

But this is as much about power as it is about privacy. Surveillance and intelligence are tools of control, at home and abroad. The history of their abuse by the US and British governments is voluminous, both in subverting and overthrowing foreign governments, from Iran to Chile, or in attacking civil rights at home, during the cold war and since 9/11.