Spender returned to London, where he worked as a freelance contributor to a number of papers and wrote his first book, a tract on old-age pensions that won him the friendship of John Morley.

Though a number of prominent individuals applied to succeed him, the owner of The Westminster Gazette, George Newnes, decided to offer the editorship to Spender, then only 33.

Veteran editor Frederick Greenwood regarded The Westminster Gazette under Spender as "the best edited paper in London"[3] and his leaders became essential reading for politicians on both sides of the political aisle.

When the latter sold the paper in 1908 to a consortium of Liberal businessmen and politicians, led by Alfred Mond, however, Spender found his cherished independence under pressure.

A growing decline in circulation and revenue led Spender and the owners to undertake the radical move of switching from an evening to a morning publication in November 1921.

His most prominent works were two biographies of Liberal Party Prime Ministers Henry Campbell-Bannerman and H. H. Asquith and a memoir of his Life Journalism and Politics.

His concern about the insufficiency of British armaments led many to brand Spender as an appeaser before the Second World War, or otherwise to praise him for his able defence of Neville Chamberlain's policy.