It has not yet completed a case.
Ms Appleby, the committee's chairman, is head of the Gray's Inn chambers where Tony Blair's wife, Cherie Booth, works.
Originally she was assisted by two other members: Sir Archie Hamilton, chairman of the backbench 1922 committee, and Robin Hodgson, the chairman of the National Conservative Convention.
Sir Archie is the Eton-educated MP for Epsom and Ewell, and a former defence minister. He has held a number of other key positions including seats on the Intelligence and Security Committee and the Committee on Standards and Privileges.
Once described as a "jumbo-sized hard-right orthodox traditional loyalist", he also has interests in a number of American defence companies.
Mr Hodgson chairs a bi-annual meeting which provides a focal point for the views and ideas of party members.
A fourth member, Nicholas Padfield QC, has also been appointed.
The group can investigate complaints that a member has acted in a way which might bring the party into disrepute, provided they are made in writing and are supported by evidence. So far the committee has not yet completed a case. It should meet at least twice a year, but only Mr Hague or the board of the Conservative Party can choose to refer a case to its internal ethics body, and so far neither has done so.
Michael Ashcroft, who has been accused of persuading the previous Tory government to lobby Belize on his behalf, is a member of the board.
Normally when the committee receives a complaint it must first decide whether there is a case to answer, and must then investigate. The person who is the subject of the complaint will be entitled to appear before the committee, and can also make written representations.
The accused will not usually be allowed legal representation, but will be allowed an appeal. That appeal will be heard by Lord Mayhew of Twysden, a former attorney-general and Northern Ireland secretary. If a complaint is upheld, the guilty party can be disciplined, suspended or expelled.
Although the committee is not meant to investigate complaints that members have broken the party line or disagreed with its policies, it may give the party leadership more control over candidate selection. For example, if it had been available to judge the cases of Neil Hamilton, accused of taking cash for questions, or Piers Merchant, caught canoodling with an assistant, it might have prevented them from standing in the 1997 election.