After graduating from Oxford, Orr joined the
Middle Temple to train as a barrister. He was
called to the English bar in July 1936. Orr was a barrister in the
chambers of
Sir Wintringham Stable at 2, Crown Office Row, which in the 1970s moved premises and became known as
Fountain Court Chambers. In the late 1940s and early 1950s, he started to build the chambers' reputation for commercial litigation, together with
Leslie Scarman QC and
Melford Stevenson QC, supported by a notable clerk, Cyril Batchelor. He was a member of the
General Council of the Bar from 1953 to 1957. Well known as a "tax devil", Orr was raised to
Queen's Counsel in 1958, and the same year was appointed as
Recorder of
New Windsor, a part-time judicial role. By 1962, he had become head of his chambers. In April 1963, he was the Guest of Honour at the annual dinner of the
Institute of Chartered Accountants of Scotland. In August 1964 he became a deputy chairman of the
Oxfordshire Quarter Sessions. In 1965 Orr was appointed as a
High Court judge, joining the
Probate, Divorce, and Admiralty Division, which was unusual, as he had only rarely appeared in it as a counsel. In 1967 he was elected as a
Master of the Bench of the Honourable Society of the Middle Temple. On 20 April 1971, together with
Sir John Stephenson, Orr was appointed a Lord Justice of Appeal. On the same day,
Sir John Passmore Widgery was created Lord Widgery and became
Lord Chief Justice. Judge Alfred Hollings QC was appointed to replace Orr in the Probate, Divorce, and Admiralty Division of the High Court, and Orr was also named as a member of the
Privy Council of the United Kingdom. In October 1966, the spy
George Blake escaped from
HM Prison Wormwood Scrubs and fled from Great Britain to the
Soviet Union, and a month later his wife, with whom he had three children, began divorce proceedings against him. In the High Court in March 1967, Orr granted her a
decree nisi in Blake's absence, on the grounds that the conviction of a spouse for
treason can amount to cruelty or constructive desertion, and also awarded the custody of the couple's three sons to Mrs Blake. On 17 December 1968, Orr granted the actress
Britt Ekland a decree nisi for divorce on the grounds of cruelty by
Peter Sellers, who did not contest the proceedings. ==Private life==