UK: National Archive withholds Mark Thatcher Oman files

Documents on “Mark Thatcher and the Omanis”, relations with the Soviet Union, Anglo-Irish negotiations, the Peter Wright “Spycatcher” case and the Profumo inquiry as well as other files have all been withheld by Downing Street.

During his tenure as Prime Minister, Gordon Brown changed the period under which historical records are released from 30 to 20 years, saying in 2007: “It is time to look again at whether historical records can be made available for public inspection much more swiftly than under the current arrangements.”

Sir Mark is alleged to have made millions from an arms deal between the UK and Saudi Arabia.

Tam Dalyell, who was an MP between 1962 and 2005, questioned why the files on Sir Mark have been retained.

He said: “My recollection is that this was a deeply unsatisfactory undercover relationship and it seemed at the time that he was taking advantage of his mother’s position.

“This not only troubled Labour politicians but a number of Tories as well.

“Again, I ask, to whose advantage is it that this information is suppressed for so long?”

There are two files on Sir Mark covering the period 1981 to 1988 – due now to be released in 2053 – entitled “Cementation contract: Mark Thatcher and the Omanis”. At the time, it was alleged Mrs Thatcher had used her influence with the Sultan of Oman to secure her son’s firm a building contract.

Separately, there are two others: “Mark Thatcher and the Omanis; other allegations against Mark Thatcher” and “Request by Electronic Data Systems to employ Mark Thatcher”.

These are marked as “temporarily retained”.

A Cabinet Office spokesperson said: “A small number of records have been retained because they contain personal data about individuals and sensitive information relating to other countries. This is in line with the requirements of the Public Records Act.”

Tim Farron, leader of the Liberal Democrats called for the files to be disclosed.

He said: “Sunlight is the best disinfectant and this decision is ludicrous. If certain sections still compromise national security or foreign relations after all this time, they should be redacted. Given the topic, it seems more likely that this is a move to avoid embarrassment.

“There is no legitimate reason for these papers to not be in the public domain and I urge the Cabinet Office to think again.”