Barnaby Miln returned in September 2000 to live with and care for Sir Derek whose health had deteriorated. In the last edition of "Who's Who" published before Sir Derek's death Barnaby Miln was named as his partner, and was the executor of his estate. Pattinson was a Freemason, initiated in 1960 in the Kaisar-i-Hind Lodge (London), and became a Royal Arch Mason in 1962 in the Oxford & Cambridge University Chapter (London). He was an officer of the United Grand Lodge of England from 1979. He was a member of the Athenaeum Club and the Savile Club. He became a Freeman of the City of London in 1973 and was a member of the Woolmen's Company and of the Parish Clerks' Company, of which he was Master 1986/7. Sir Derek was diagnosed with hydrocephalus in 2000. He died in London on 10 October 2006 and his ashes are buried in Westminster Abbey. He had held numerous other appointments including membership of the Archbishops' Commission on Church and State (1966–70) and the British Council of Churches (1972–90), the vice-chairmanship of the Grosvenor Chapel Committee (1973–81), the chairmanship of Liddon Trustees (1972–2001), the William Temple Association, and of the English Friends of the Anglican Centre in Rome (1985–2001), and the principalship of the Society of the Faith (1992–2001). He was Churchwarden of St Michael's, Cornhill and Parish Clerk of St Luke's, Old Street.