Heavily redacted documents show how determined British security and intelligence agencies – including GCHQ – were to maintain an effective presence in Cyprus after the strategically important island became independent.

MI5 and MI6 helped to ensure that Britain would continue to be able to operate from two UK sovereign base areas in Cyprus. The files, released by the National Archives on Friday, contain numerous references to Box 500 (MI5) and Box 600 (MI6).

They also refer to the need to "maintain liaison with other British Intelligence Services based in Cyprus". What the unredacted files do not mention by name is GCHQ, the government's eavesdropping agency at the centre of the revelations about mass surveillance of diplomatic, political and personal data by the US whistleblower Edward Snowden.

However, there is a telltale reference which escaped the censor's notice. One of the memos of the Sovereign Areas Intelligence Committee, marked Top Secret, was copied to a Sir Eric Jones. Jones was director of GCHQ at the time.

The fact that GCHQ has a listening station at Ayios Nikolaos in the UK's eastern sovereign base area in Cyprus was first revealed more than 30 years ago. It is clear that all references to it which were in the files released on Friday have been obscured by Whitehall's weeders.

The listening post has intercepted communications in turbulent areas of the Middle East ever since the second world war. Documents released by Snowden to the Guardian reveal that half the cost of running Ayios Nikolaos is paid for by the US – clear testimony to the value of the listening post.

The files also reveal that Archbishop Makarios, the Greek Cypriot leader who became the first president of Cyprus when the island gained independence in August 1960, agreed not only to the UK bases but to British help in setting up his country's own security and intelligence agencies.

Just four years earlier, he was deported by the British colonial authorities and exiled to the Seychelles in the Indian Ocean after refusing to denounce the use of violence. Britain accused him of "actively fostering terrorism".