The St Marylebone by-election of 22 October 1970 was held after Conservative Member of Parliament (MP) Quintin Hogg became a life peer. The seat was retained for the Conservatives by Kenneth Baker, who had lost his previous seat of Acton at the general election four months earlier; Baker would go on to represent the Mole Valley seat in Surrey and become a long-serving Cabinet minister.

1970 St Marylebone by-election

← June 1970 22 October 1970 Feb. 1974 →
Constituency of St Marylebone (UK Parliament constituency)
First party Second party Third party   Lab Lib Candidate Kenneth Baker Keith Morrell Michael Vann Party Conservative Labour Liberal Popular vote 10,684 4,542 1,038 Percentage 63.49% 26.99% 6.19% Swing 1.40% 2.32% 2.41%
A map of parliamentary constituencies within the County of London at the time of the by-election, with St Marylebone highlighted in red.
MP before election Quintin Hogg Conservative Subsequent MP Kenneth Baker Conservative