Amnesty is taking legal action against the US and UK governments, challenging “the lawfulness of their indiscriminate mass surveillance programmes.”
The human rights campaigning group will head to the European Court of Human Rights in Strasbourg on Friday because, it says, "every legal avenue in the UK has been exhausted."
Amnesty's announcement coincides with the results of a large-scale surveillance poll of 15,000 people from 13 countries and the launch of its global campaign #UnfollowMe.
According to Amnesty, its survey shows there is strong global opposition to the US monitoring internet and mobile phone use with 71 per cent of respondents saying they were strongly opposed to surveillance.
In Britain, 63 per cent of respondents were opposed to US surveillance of UK internet and mobile phone use, with 21 per cent of people in favour. The strongest opposition to the US intercepting, storing and analysing personal data came from Brazil (80 per cent against) and Germany (81 per cent).
In Britain, 44 per cent said they thought the UK government should not be carrying out mass surveillance versus 36 per cent in favour.
Kate Allen, Amnesty UK director, said: "This highlights the need for a properly-informed debate here in the UK about privacy rights and legitimate security concerns. Instead of open debate, we have seen legislation rushed through without normal parliamentary scrutiny, secret court hearings and absolutely no proper independent oversight to hold the spies to account."
"Nobody disputes the necessity of properly-targeted surveillance, but the government must not ride roughshod over the rights of the very people they’re supposed to protect."
Salil Shetty, Amnesty International’s secretary general, added: "President Obama should heed the voice of people around the world and stop using the internet as a tool for collecting mass data about peoples’ private lives. Today’s technology gives government’s unprecedented power to watch what we do on the internet. We need independent scrutiny to watch the watchers so that power is not abused."
The #UnfollowMe campaign urges governments to make efforts in supervision and transparency around mass surveillance.