 On 7 January 2015 the Queen co-signed Letters Patent that created her consort HRH Prince Philip, Duke of Edinburgh a Knight of the Order of Australia, on the same basis as applied to Prince Charles in 1981.This award was publicly announced in the Australia Day Honours list of 26 January 2015, along with the knighthood of Air Chief Marshal Angus Houston, former Chief of the Defence Force.On 2 November 2015, Abbott's successor as Prime Minister Malcolm Turnbull announced that the categories of knight and dame in the Order of Australia would again be discontinued, although existing holders of the titles would not be affected.