He fought several parliamentary elections for the party, became chief executive of Conservative Central Office from 2002 to 2003 and then ran Steve Norris' campaign to become Mayor of London in 2004.
In October 2002, MacGregor accepted undisclosed libel damages and a public apology at the High Court over allegations in Punch magazine.
Mr Justice Eady was told that MacGregor had never been chairman or a member of the Young Monday Club as had been falsely claimed by the magazine.
Mr MacGregor also successfully sued the Daily Mail for libel over similar allegations related to his period as Chairman of the FCS.
In 2002, MacGregor was named the new chief executive of the Conservative Central Office[8] appointed by Iain Duncan Smith on becoming Party leader.
"[12] John Bercow praised MacGregor's loyalty, but also lamented the loss of his talent and creativity, adding "the modernising agenda has been at best, sidelined and at worst, lost".
Allegations which surfaced concerning the payment, out of the Parliamentary purse, of wages to Betsy Duncan Smith led to an investigation into the conduct of IDS by the House of Commons Committee on Standards and Privileges.
The Sunday Telegraph revealed that the party had been re-investigating the saga surrounding payments made by the former leader, Iain Duncan Smith, to his wife, Betsy, for secretarial work in 2003.
MacGregor and Gearson were reinserted on the parliamentary candidates list, despite protests from the traditionalist Cornerstone Group of backbenchers,[16] although he was not later reselected by the Thanet South Conservative Association, losing to Laura Sandys who later became the MP.