Complex sentence: He later held political office under Harold Macmillan as a Lord-in-Waiting (government whip in the House of Lords) from 1957 to 1961 and as Joint Under-Secretary of State for the Home Department from 1961 to 1962.
Split into simpler sentences: He later held political office under Harold Macmillan as a Lord-in-Waiting (government whip in the House of Lords) from 1957 to 1961. Briefly he was promoted a junior minister as Joint Under-Secretary of State for the Home Department from 1961 to 1962.