This video from Britain says about itself:
20 July 2016
Files on Mark Thatcher’s dealings in Oman to remain secret for now.
From daily The Morning Star in Britain:
Still in dark over Mark Thatcher’s deals
Thursday 21st July 2016
DOWNING STREET files relating to the controversial business dealings of Mark Thatcher will remain closed to the public for years to come, it has emerged.
Under legislation relating to public records, official files should be released to the National Archives at Kew after 30 years unless there are specific reasons for them not to be disclosed.
But the latest release of files to the archives includes two files entitled Cementation Contract: Mark Thatcher and the Omanis that cover the period from 1981 to 1988 which are listed as being retained for 65 years, meaning they will not be released until 2053.
Two other files — one entitled Mark Thatcher and the Omanis; Other Allegations against Mark Thatcher and the other Request by Electronic Data Systems to Employ Mark Thatcher — have been marked “temporarily retained” with no date for release.
The Cementation contract refers to a deal by Cementation International — a subsidiary of the Trafalgar House property, construction and engineering conglomerate for which Mr Thatcher was working as a consultant — to build a new university in Oman.
When details emerged in the press in 1984, it led to allegations that his mother, the then prime minister Margaret Thatcher, had used her influence with the pro-British Sultan Qaboos of Oman to secure the contract for her son’s firm.
In the ensuing furore Mr Thatcher moved to the US. The Cabinet Office said a “small number” of records had been held back because they contained “personal data about individuals and sensitive information relating to other countries.”
Sir Mark Thatcher is refused a US visa over criminal record: here.