Born in 1905, he was brought up in County Durham and never lost his North Country tones and attitudes. After school, he trained as a chartered accountant, qualifying in 1928. Ten years later he changed career and became a solicitor, and was clearly doing well when the outbreak of the Second World War took him into war work.
In 1943, he went to the Press Censorship division of the Ministry of Information and worked under Cyril Radcliffe KC, later Viscount Radcliffe, who formed a high opinion of his capacities. After the war, with Radcliffe's encouragement and support, Sopwith was taken on by the Board of Inland Revenue as a solicitor. At the age of 40, he was told that he was unlikely to get to the top, but in the event, by dint of hard work and his high legal ability, he worked up - after a two-year stint from 1961 to 1963 as Public Trustee - to become the Solicitor to the Board of Inland Revenue in 1963. He retired from the post on reaching the age of 65 in 1970.
The same year he became a Deputy Secretary in the Division of the Cabinet Office responsible for preparing the accession of the United Kingdom to the European Communities. As such he was chairman of a small legal committee, which was part of a team responsible for preparing the instructions for the European Communities Bill of 12 clauses and four schedules. This was carried into law in 1972, and brought about British entry into the Communities.
The Bill was hard fought in both Houses, but especially in the Commons, where its Second Reading was passed by only seven votes in emotional scenes. As a piece of drafting it was exceptional in that, although a Bill of the highest constitutional importance, it was passed into law through both Houses without one word's being amended. In later years, Sopwith was wont impliedly to regret that the Government White Paper (The United Kingdom and the European Communities, Cmnd 4715) was not more forthright about the implications, both constitutional and economic, of British membership of the Communities.
The final part of his career began when, at the age of 69, he was given the newly created post of Second Counsel to the Chairman of Committees at the House of Lords, in practice the learned counsel to the House for its European Communities Committee on all matters of European law. He served with Lord Diplock, in particular in his role as Chairman of the Law Sub-Committee of the European Communities Committee.
Diplock was only persuaded to take on that job in addition to that of a working Law Lord by being promised legal backing of a high order. In Sopwith, the promise was redeemed and they became a formidable duo and the best of friends. In both cases they were pro-European, but with an active sense of the limits of EC competence and the just requirements of British national needs.
Sopwith was one of the creators of the system of scrutiny by Parliamentary Committee of European Community proposals - which in time come to affect all our lives - by examining them at an early stage, hearing evidence, elucidating them with the help of experts, reporting on their probable effects and whether desirable or not, and whether requiring amendment. He, with his parliamentary masters and colleagues, realised that it was only by the hard work of understanding the policy issues involved that one could hope to affect the outcome of complicated negotiations in the Council of Ministers.
In the late Seventies and early Eighties Sopwith was instrumental in writing a notable series of reports on the EC company law harmonisation programme, such as Group Accounts, competition policy (Competition Practice), the supervision of the Community's finances (EEC Budget), and on the Community institutions (Direct Elections to the European Parliament). He eventually retired in 1982 at the age of 77.
Charles Sopwith was of the old school, not given to the expression of his emotions; not for him the instant intimacy of today. He had the highest standards and never countenanced the second-rate in others or spared himself. Though quiet and undemonstrative, he was invariably warm and supportive in relations with colleagues and staff. He will be remembered for his old-fashioned courtesy combined with a gentle twinkle. His dry sense of humour would extract unexpected amusing aspects from all persons and situations around him. He was deeply musical, and gave much voluntary effort to various musical charities and was for years a director and honorary fellow of the Royal Academy of Music.
He married, at the age of 40, Ivy Violet Yeates, but their happy marriage was prematurely brought to a close when she died in 1968, and he never remarried. Instead he devoted his later years to his nephews and nieces and their families, with whom he was able to relax and enjoy himself, especially in retirement, and give vent to his keen humour.
Charles Ronald Sopwith, solicitor: born South Shields, Co Durham 12 November 1905; Assistant Solicitor, Board of Inland Revenue 1952-56, Principal Assistant Solicitor 1956-61, Solicitor 1963-70; Public Trustee 1961-63; Kt 1966; Deputy Secretary, Cabinet Office 1970-72; Second Counsel to Chairman of Committees, House of Lords 1974-82; married 1946 Ivy Violet Yeates (died 1968); died Berkhamsted, Hertfordshire 15 November 1996.