Crispin Aubrey: Journalist convicted under the Official Secrets Act in the 'ABC Trial'

Crispin Aubrey, who has died of a heart attack at the age of 66, was a journalist who in 1977 found himself the centre of a news story when he was arrested and accused of breaking the Official Secrets Act. Aubrey was the "A" of the ABC case which saw two journalists and a former member of Signals Intelligence tried in High Court amid scenes which were at times chaotic, and which brought into question the use of secrecy legislation, ensuring that it was never to be used in the same way again.

Aubrey was born in Chipstead in Surrey into a middle class family; his mother Margery was an illustrator, his father Laurie an insurance broker. He was educated at Leighton Park, a Quaker School, and won a scholarship to read English at Christ Church College, Oxford. Behind a very English façade was a quirky, quizzical character with a laidback sense of humour who didn't like being pushed about, had a strong sense of justice and wasn't afraid of taking on the establishment.

After starting out as a journalist on the Hampshire Chronicle, Aubrey joined Time Out as it campaigned to expose the dirty secrets of the British and American governments which had led to deportation orders against two Americans, the former CIA operative Philip Agee and Time Out's own reporter Mark Hosenball, who had co-written an expose of GCHQ, the government's communcations headquarters and the centre for Signals Intelligence. Aubrey, whose major interests had been the environment, became involved with the fight, ultimately unsuccessful, to stop them from being thrown out of the country.

In February 1977, Aubrey and a freelance science journalist, Duncan Campbell, were sent to interview John Berry, a former member of Signals Intelligence who, angry at the deportations, had contacted the magazine. The two men were arrested as they left Berry's flat; Time Out's phones had been tapped. Berry was also taken into custody. All three were charged under Section 2 of the Official Secrets Act 1911 which forbade the disclosure of any official information, and Aubrey and Campbell with unauthorised receipt of classified information. Further charges were later added under the more serious Section 1 of the Act which accused them of felony and acting against the state, offences with a maximum sentence of 14 years.

Over the next year while awaiting trial the three were subjected to intimidation and harassment, including house searches – one of which saw the police raiding Aubrey's house and searching his baby daughter's bed; they were trailed by plain clothes officers and had to report daily to the police. Through it all Aubrey and his wife Sue remained stoical.

The ABC Defence campaign, supported by the National Union of Journalists and civil liberty groups, received widespread publicity as anger grew at the charges levelled against the men under an outdated Act, and at the way in which the trials were conducted. The first trial collapsed in September 1978 following the identification of a member of the jury as a former SAS officer. When the second trial opened a month later, the prosecution admitted that much of the secret information disclosed by Berry was already in the public domain and dropped the Section 1 charges.

Further derision came as prosecution witnesses, testifying anonymously under letters of the alphabet – in particular witness B, Colonel Hugh Johnstone, head of Signals Intelligence, were identified to the public outside the courts, and later by NUJ members at their annual conference. To Aubrey, the prosecution's attempts at secrecy were "the security services trying to cloak their witnesses in anonymous letters and make the whole affair appear more sinister."

In November, Aubrey, Berry and Campbell were found guilty of breaking the Official Secrets Act but given non-custodial sentences. In 1989, Section 2 was amended to make it an offence to divulge information only in relation to six specific categories.

Following the trial, Aubrey and his wife moved to Somerset, where they ran a small farm. In 1981 he wrote Who's Watching You? Britain's Security Service and the Official Secrets Act. He worked as a freelance, writing and campaigning about environmental issues, and edited Wind Directions, which supported wind power and fought passionately against the building of nuclear plants.

He also published two books on environmental issues, Meltdown, the Collapse of the Nuclear Dream and Thorp: the Whitehall Nightmare, and became involved with the campaign to stop a nuclear reactor – the largest proposed for this country – being built at Hinkley in Somerset. He remained an active member of the Stop Hinkley group for the rest of his life. Though the campaign was at first successful, plans were resurrected a few years ago, leading him to taking up an active role once more.

Katy Attwater of the Stop Hinkley Group was impressed by the manner in which Aubrey fought for his beliefs. "He was," she said "a completely dedicated environmentalist. He understood the issues, guided wisely and wrote and spoke eloquently. An honourable man respected by everyone, even the other side. He has left us in a very strong position to make sure that no nuclear power station is ever built again."

Aubrey became involved with the nearby Glastonbury festival in the early 1990s, and in 2004, along with John Shearlaw, edited the book Glastonbury Festival Tales. Michael Eavis, founder of the Festival, remembered how strong Aubrey's environmental beliefs were: "He was a resolute campaigner for green issues who kept up the pressure on me constantly."

Crispin Aubrey, journalist and environmental campaigner: born Chipstead, Surrey 3 January 1946; married 1968 Susan Jacob (three daughters); died Bridgewater, Somerset 28 September 2012.