UK surveillance agency GCHQ has been working closely with US government agencies such as the NSA through the sharing of classified intelligence for some time, and has recently been officially censured for not disclosing the nature of its relationship.
The Investigatory Powers Tribunal said that GCHQ failed to clarify details about how it shared data from its mass internet surveillance project until sometime around December of last year. Apparently, this is IPT's first ruling against an intelligence agency in its 15-year history.
In December, the IPT ruled that the system of UK intelligence collection did not breach the European Convention of Human Rights, despite a complaint by campaign groups including Privacy International and Liberty. However, now the tribunal ruled that the system did "contravene" human rights law, until December 2014, when the GCHQ revealed information about its relationship with the NSA.
The IPT stated that, prior to December, GCHQ was in violation of articles 8 or 10 of the European Convention of Human Rights:
"The regime governing the soliciting, receiving, storing and transmitting by UK authorities of private communications of individuals located in the UK, which have been obtained by US authorities pursuant to Prism and... Upstream, contravened articles 8 or 10 [of the European Convention of Human Rights]."
The tribunal left off by saying that the agency is now fully compliant.