Known in several former colonies as “Operation Legacy”, Whitehall set out a list of the types of material it wanted removed, including anything which “might embarrass members of the police, military forces, public servants (such as police agents or informers)”. Once “dirty” documents had been removed the remaining “clean” material was passed to a new strata of administrators overseeing independence processes who were deliberately not told about the sifting process.
It also ordered the destruction or removal of “all papers which are likely to be interpreted, either reasonably or by malice, as indicating racial prejudice or bias”.
Under the rules, all material marked “Top Secret” or “Secret” was either sent back to Britain via the RAF or the navy, or destroyed either by burning or “placed in well-weighted crates and sunk in deep and current free water at the maximum practicable distance from shore”.
Among the documents is a note that officials should carefully control any bonfires of secrets and avoid a situation similar to Indian in 1947 when the local press was filled with reports about the “pall of smoke” which fell over Delhi at the end of the Raj as British officials burnt their papers.
If anyone tells you that Britain was a "good empire", they're lying. They're simply an empire which burned all the evidence. And as a result, they've largely gotten away with their crimes.