A question often posed by historians and many others. This post refers to 1978-1979 in Southern Africa, with Rhodesia as the key focus. For complicated reasons I have long had an interest in the history of Rhodesia, now Zimbabwe and visited once for a holiday in 1985.

Tonight a BBC Radio Four documentary 'Document' in a programme entitled 'Did UK warn Mugabe and Nkomo about assassination attempts?' reveals the facts behind:
Successive British governments have accused Zimbabwe's President Robert Mugabe of brutal, corrupt and incompetent rule, but new evidence suggests that without British help, he might not have lived long enough to come to power.
Link to BBC News summary, a podcast will be available tonight after the broadcast:http://www.bbc.co.uk/news/world-africa-14311834

Some Rhodesians have blamed 'perfidious Albion' having access to Rhodesia's inner secrets, in particular using traitors and one Ken Flowers, the CIO Director (Rhodesia's external intelligence agency). So this will reinforce their suspicions, citing the British Foreign Secretary Lord Owen can clear up that mystery too:
The head of Rhodesian Intelligence, Ken Flowers, was also on our side. So I was well aware of what Ken Flowers was claiming was being done, and I used to read the reports.
Ken Flowers is deceased, as are many of those he worked with and those who suspected him.