On 29 January, Shawcross was reappointed for a further three years to the post he has occupied since October 2012.
The same day Sir Stephen Bubb, chief executive of Acevo, wrote to the Cabinet Office expressing concern that this had been done "on the quiet" and asking whether the correct procedures were followed.
Sir Jeremy Heywood, Secretary of the Cabinet and head of the civil service, responded to Bubb on 4 February, saying that due process was followed.
The letter says: "The reappointment of William Shawcross as chair of the Charity Commission was a decision taken by the Minister for the Cabinet Office, Francis Maude. Decisions on reappointment are matters for ministers and there is no requirement for a separate appointments committee or selection panel."
Reappointment requires a performance appraisal "that is at least satisfactory", it says. This was carried out by Richard Heaton, permanent secretary at the Cabinet Office.
A story in The Times newspaper on Acevo’s original letter quoted a source at the Cabinet Office as saying "no rules had been broken", although a Cabinet Office spokeswoman speaking to Third Sector at the time was unable to provide an on-the-record statement to that effect.
Rob Wilson, the Minister for Civil Society, told Third Sector earlier this month that he believed "everything was done as it should have been".