Menneskerettsdomstolen i Strasbourg skal se på lovligheten av britiske lover som gjør det mulig å holde tilbake mistenkte i ni timer på flyplasser og ved grensekontroller.
Det var denne adgangen som ble brukt da kjæresten til Glenn Greenwald, Miranda, ble holdt tilbake på Heathrow. Han var muldyr for 58.000 hemmelige dokumenter som stammet fra Edward Snowden.
At Strasbourg vil vurdere lovligheten av denne adgangen gjør britene fly forbannet.
The European Court of Human Rights has given the go-ahead to a legal challenge seeking to strike out the controversial powers, which were used earlier this year to detain the partner of a Guardian journalist who was carrying 58,000 stolen British secret documents through Heathrow airport.
Strasbourg judges have agreed to a full hearing in the new legal challenge even though a thorough inquiry by British MPs and peers has already concluded the powers are compatible with human rights law.
The appeal, brought by a British investment banker who was detained for more than four hours under the legislation, could lead to the power being ruled illegal.
Such a move would inevitably inflame tensions over the court’s interference in British domestic affairs and comes after the body demanded that prisoners be given the right to vote, to the fury of ministers and MPs.
The Home Office has described the powers under Schedule 7 of the Terrorism Act 2000 – which allow police to detain suspects at ports and airports for up to nine hours without reasonable suspicion – as a “key part of the United Kingdom’s border security arrangements”.
Amid concerns the power is operating unfairly ministers have already launched a review, but have insisted: “Schedule 7 examinations have produced information which has contributed to long and complex intelligence-based counter-terrorist investigations.”
Earlier this month members of Parliament’s Joint Committee on Human Rights found there was a “clear” case to retain the powers.
MPs and peers on the committee said allowing police to stop and search suspects at airports without suspicion were “not inherently incompatible” with human rights laws.
The powers were used to detain Mr Miranda, the partner of Glenn Greenwald, a Guardian journalist who has written a series of stories based on leaks from former CIA employee Edward Snowden.