
The move ends months of speculation about his future as chief executive of the Telegraph Group and chief operating officer of Hollinger International, which is the ultimate parent of the Daily Telegraph, the Chicago Sun-Times and the Jerusalem Post.
A fellow Canadian, Colson is the last of Lord Black's senior supporters to hang on to their jobs. According to a report in the Financial Times Colson had planned his departure several months ago.
Last week it was reported that Colson had rejected calls to resign from the board of Hollinger International because of the damage it would do to the newspapers at a time considered critical for the sale of Hollinger International's assets.
His exit follows testimony at the court case in the US that showed Colson had helped Lord Black in his attempts to sell Hollinger Inc to the Barclay Brothers without board approval. He was said to have given over confidential information to help the billionaire twins.
However this has been disputed by others close to the deal. Colson is said to only have responded to questions following speculation about Richard Desmond's intentions.
Colson has hung on to his job partly because unlike other Hollinger executives he was not accused of receiving improper payments.
Lord Black was ousted first as chief executive and then as chairman of Hollinger International after a dispute erupted about payments he and other executives collected.
Colson's expected exit comes as second round bids are due from half a dozen companies including USA Today publisher Gannett, Express Newspapers, Daily Mail & General Trust and German media giant Axel Springer.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .