He was born, of Irish descent, in Grenada, West Indies and came to the United Kingdom to study medicine at Glasgow University in 1904. while at University he was active in the Fabian Society and founded the students' Irish Nationalist Club. After qualifying, he worked in a number of Glasgow mental hospitals and then served as a doctor in France during World War I, and then entered general practice in London, initially at Greenwich, later Camberwell and finally at Paddington.
Morgan contested the South London constituency of the Camberwell North West at the 1922 general election, but lost by a wide margin to the National Liberal MP Thomas James Macnamara. He stood again at the 1923 election, when Macnamara had re-joined the Liberal Party, and lost by only 80 votes. In 1924, Sir Edward Taswell Campbel won the seat by only 194 votes, and Morgan finally won the seat at the 1929 general election.
However, the Labour Party split at the 1931 general election over fiscal policy; Prime Minister Ramsay MacDonald had left the party to form a National Government with the support of the Conservative Party and some Liberals, and Labour's national share of the vote fell disastrously from 37% to 31%. In most seats, Liberal and Conservative candidates agreed a single candidate to stand against Labour, and as a result Labour retained only 52 of the 287 seats which it had won in 1929. Morgan's Camberwell seat was one of those lost.
He did not stand for Parliament again until 1940, when the Labour MP William Kelly resigned his Rochdale seat. At the by-election in July 1940, Morgan was elected unopposed. He was re-elected in 1945, but with a majority of only 10%, he moved at the 1950 general election to the safer Warrington seat, which he won with a comfortable 19% majority. He was re-elected in Warrington in 1951 (when the Conservatives won Rochdale), and retired from the British House of Commons at the 1955 general election.
In between his periods in Parliament, Morgan returned to medical practice. In 1936 he worked with Charles Brook and other members of the Labour-affiliated Socialist Medical Association to found the Spanish Medical Aid Committee, to provide supplies and a uniformed medical unit to the Republican side in the Spanish Civil War. He served as a member of the Confederation of Health Service Employees (COHSE) union National Executive Committee and COHSE's Medical Guild from 1946-1951. Morgan died in 1956, aged 70.
- Craig, F. W. S. (1983) . British parliamentary election results 1918-1949 (3rd ed.). Chichester: Parliamentary Research Services. ISBN 0-900178-06-X.
- Leigh Rayment's Historical List of MPs [self-published source][better source needed]
- Hansard 1803–2005: contributions in Parliament by Hyacinth Morgan
- Documents on Morgan's involvement in the Spanish Civil War from "Trabajadores: The Spanish Civil War through the eyes of organised labour", a digitised collection of more than 13,000 pages of documents from the archives of the British Trades Union Congress held in the Modern Records Centre, University of Warwick
|Parliament of the United Kingdom|
|Member of Parliament for Camberwell North West
|Member of Parliament for Rochdale
|Member of Parliament for Warrington