Born in Manly, New South Wales, the son of Charles Croker Longmore and Janet Murray, he was educated at Benges School, Hertford, and Foster's Academy, Stubbington,[1] before entering Dartmouth Naval College.

He obtained flying certificate No.72 in April 1911[1][2] at an RAeC meeting that also awarded licences to the pioneer naval aviators C. R. Samson and Wilfred Parke.

[2] The outbreak of the Second World War found Longmore an air chief marshal and in charge of RAF Training Command.

[2] The Oxford Dictionary of National Biography says the following of Longmore during the first few months of 1941: In retirement he was vice-chairman of the Commonwealth War Graves Commission.

The popular Labour politician Sir Stafford Cripps, who had returned to Britain following a spell as Ambassador to Russia, was brought into Churchill's War Cabinet.

Kendall revealed wartime production figures in his election hustings speeches to criticise the government, but in a way that breached the Official Secrets and the Defence of the Realm Acts.

The Grantham Communist party in line with the position taken by their national headquarters, circulated a leaflet that urged electors to vote for the Conservative Longmore, so as to show solidarity with the Red Army.

[1] One of their sons, Wing Commander Richard Maitland Longmore OBE, was killed in action on 4 October 1943, in the course of an attack on a U-boat.