The money was used to expand Reuters coverage of the Middle East and Latin America and hidden by increased news subscription payments to Reuters from the BBC.
"We are now in a position to conclude an agreement providing discreet Government support for Reuter services in the Middle East and Latin America," according to a redacted 1969 British government document marked "Secret" and entitled "Funding of Reuters by HMG".
"HMG's interests should be well served by the new arrangement," said the document, which was declassified last year. HMG stands for Her Majesty's Government.
The extent of influence - if any - that the government was able to exert over Reuters news in return for the money is unclear from the documents, which detail a 1969 secret British government financing deal for Reuters.