Lascelles was born on 18 September 1908, the fourth son of Alfred Lascelles of
Darlington, a councillor and JP. He was educated at
Durham School and
St John’s College, Cambridge. He was called to the Bar by the
Inner Temple in 1930. Lascelles joined the
Sarawak Civil Service in 1932, and proceeded to serve in various posts throughout the territory including:– Registrar of the Supreme Court and Official Assignee (1933); Officer at
Sibu and magistrate (1933); District Officer in the
Third Division (1934), and in the
Oya,
Kapit and
Miri Districts. In 1940, he was assistant Secretary for Defence. On the outbreak of
World War II he was District Officer and Naval Reporting Officer in Miri. He was captured by the Japanese and imprisoned in
Kuching from 1942 to 1945. After the War, he returned to Sarawak as District Officer, Miri. In 1948, he was appointed a circuit judge of Sarawak. In 1950, he presided over the trial of ten Malays accused of
the murder of the Governor of Sarawak,
Duncan George Stewart. After Lascelles with five assessors found nine of the accused guilty, two of the men, considered the leaders, were subsequently hanged. In 1951, he joined the Colonial Legal Service and, after a year serving as acting puisne judge, he was confirmed in office as Puisne Judge of Supreme Court of Sarawak,
North Borneo and
Brunei, remaining in the position from 1952 to 1962. Fluent in the Malay and Dayak languages and familiar with their customs, it was said that, "he brought an important part in bringing to the judicature, a deep and sympathetic understanding of the local peoples' problems". After 30 years' service in Sarawak's administrative and legal services, he retired to England in 1962 where he served as Legal Chairman of the Pensions Appeal Tribunals (1964–1974); Chairman of the Medical Appeal Tribunals (1967–1974), and Member of the Mental Health Review Tribunal (1967–1974). == Personal life and death ==