Britain’s top spy agency -- Global Communications Headquarters (GCHQ) -- illegally spied on Amnesty International, according to an investigatory tribunal. The latest findings directly contradict the government's earlier stance on the matter.

Confirmation that the international rights group was under surveillance emerged late on Wednesday, when Amnesty revealed that the Investigatory Powers Tribunal (IPT) sent it an email that corrected an earlier judgment.

In a June 22 email to Amnesty, the IPT ruled that communications from the Egyptian Initiative for Personal Rights and the South African non-profit Legal Resources Center had been illegally collected and examined. It was responding to a complaint that Amnesty and nine other human rights groups had filed in April.

However, in another email sent on Wednesday, the IPT clarified that it was Amnesty itself, and not the Egyptian group, that was being spied on alongside the South African group. It did not clarify when or why Amnesty was spied on, or what the information was used for.

The illegal surveillance was found to breach the U.K.'s Regulation of Investigatory Powers Act, which stipulates how long collected data can be retained. Amnesty had been one of the original claimants in the case, but the IPT had initially made “no determination” on its complaint, which meant that either Amnesty’s data had not been intercepted or it had been done through legal channels.

Amnesty condemned the practices detailed in the revelation. “The revelation that the UK government has been spying on Amnesty International highlights the gross inadequacies in the UK’s surveillance legislation,” Salil Shetty, Amnesty’s secretary general, said in a statement. “If they hadn’t stored our communications for longer than they were allowed to by internal guidelines, we would never even have known. What’s worse, this would have been considered perfectly lawful.”

The revelation means that Amnesty joins a growing list of nonprofits and organizations, including the United Nations children’s charity Unicef and the French medical group Medecins du Monde, that have been targeted for surveillance by GCHQ in collaboration with America’s National Security Agency.