Amongst the censored files from 1986 and 1987 are 15 relating to Saudi Arabia, including one on the “sale of Tornado and Hawk aircraft” and “training for Saudi Arabian special forces”, The Times reports.
The government retained another 27 papers connected to Prince Charles and Lady Diana’s visit to the Middle East in 1986.
A further 40 files relating to India, including files on UK defence sales and the Indian national security guard, were also withheld.
After 30 years, all documents held by government departments must be passed to the National Archives at Kew under current rules. However, departments can apply to have them withheld or redacted.
The number of documents being withheld is rising, the Advisory Council on National Records and Archives, which rules on such requests, said in its annual report.
In 2015-16, the council overturned just four out of 952 censorship applications, and three out of 793 the year before. Last year, however, it overturned 22 decisions out of 986.
Robert Barrington, executive director of Transparency International UK, said that openness over public records was an “important part of rooting out corruption”. He added: “This report suggests there is still a culture of opacity within many government departments.
A lack of disclosure can often lead to concerns that the government has something to hide and therefore transparency is the best measure to ensure public trust
The government continues to censor information relating to Saudi Arabia’s relationship with to the UK until the present day. At the beginning of June 2017, the Home Office admitted the “very sensitive” findings of an investigation into Saudi funded extremism in the UK would also not be published.
The inquiry into the foreign funding of jihadi groups in Britain was authorised in 2015 by former Prime Minister David Cameron in exchange for Liberal Democrat support for the extension of British airstrikes against Islamic State into Syria.
The government has also withheld information regarding non-governmental Islamist groups. In 2015, a report into the Muslim Brotherhood was only partially released, the rest remaining classified.
The Brotherhood is the largest International Islamist organization in the world and is classed as a terror group across much of the globe.
The findings that were made public stated that the Sunni Islamist group has exerted “significant influence” on the UK’s largest Islamic organisation, the Muslim Council of Britain (MCB).
The report also said the Brotherhood had “facilitate funding for Hamas” and that senior figures in the organization had to justified attacks against coalition forces in Iraq and Afghanistan.