The document, leaked by former U.S. National Security Agency contractor Edward Snowden, reveals Britain's Government Communications Headquarters worked with German, French, Spanish and Swedish intelligence services to create bulk surveillance systems, the British newspaper The Guardian reported Friday.
GCHQ officials are quoted in the document as expressing admiration for Germany's technical abilities in collecting electronic information. In 2008, as Britain was developing its Tempora system, GCHQ said Germany's Federal Intelligence Service (BND) had "huge technological potential and good access to the heart of the Internet."
The document says GCHQ provided German officials legal advice "in making the case for reform or reinterpretation" of the country's restrictive laws on intelligence gathering.
GCHQ applauded France's General Directorate for External Security (DGSE) as "a highly motivated, technically competent partner, who have sown great willingness to engage in IP [Internet protocol] issues."
The British spy agency said France had a comparative advantage because of its relationship with a telecommunications company the report did not name, which GCHQ also hoped to take advantage of.
British and French spy agencies co-hosted a conference in 2009 about Internet-monitoring initiatives and four months later reported on its success at cracking commercial online encryption.
In 2008, GCHQ reported a "commercial partner" was supplying the Spanish National Intelligence Center (CNI) with equipment. GCHQ described CNI as "a very capable counterpart," especially in the area of "covert intelligence ops."
The British agency took some of the credit in 2008 when the Swedish parliament passed a law allowing the country's intelligence service to tap into fiber optic cable.
"GCHQ has already provided a lot of advice and guidance on these issues and we are standing by to assist the FRA further once they have developed a plan for taking the work forwards," the document says.
GCHQ worked with Dutch intelligence services but noted "the Dutch have some legislative issues that they need to work through before their legal environment would allow them to operate in the way that GCHQ does."
The agency said it had difficulty working with the Italian intelligence agencies because they were "fractured and unable/unwilling to cooperate with each other."