The 1973 British Labour Party leadership election was held following the resignation of Harold Wilson.
Foreign Secretary Roy Jenkins was the favorite to win, and had the endorsement of leading centre-left Newspaper the Guardian. Jenkins himself was confident of victory on the second ballot, believing that a three way contest between himself, Callaghan and Castle would result in a victory for himself.
Home Secretary James Callaghan was viewed as the only other likely victor after Jenkins, and was seen as his main rival. Callaghan himself later wrote in his memoirs that he thought it unlikely he would win, and privately told his confidants that he would withdraw after the first ballot if Jenkins was the clear winner.
Chancellor Denis Healey was thought of as a possible compromise candidate between the tribal cliques of Jenkinsites and Callaghanites, a man who could unite the right and lead the party for quite a long time (he was not yet 56, and only three years older than Jenkins).
The other candidates (Castle, Crosland, Shore) were not seen as real leadership figures, but merely trying to raise the profile of their own pet causes (Anti EEC for Castle and Shore, Social Democracy for Crosland).
First Round Result
Shore was eliminated from the contest and Crosland withdrew. Shore endorsed Castle (the only other anti EEC candidate) whilst Crosland endorsed Jenkins.
The narrowness of the result was a surprise to many pundits, who expected Jenkins and Callaghan to gain over 60% of the total votes (they actually got just over 45%). Castle's third place finish was a particular surprise
Castle was eliminated from the contest, coming last by one vote. Castle refused to endorse any other candidate, but ironically the majority of her voters voted for Callaghan (her bitter enemy) in the third ballot.
As with the first round of voting, the narrowness of the result was a surprise to many, particularly the fact that Castle was eliminated by only one vote.
Healey was eliminated from the contest, resulting in a run off between Jenkins and Callaghan. Healey refused to endorse either candidate, however he later revealed that he voted for Callaghan.
Before the third round of voting many predicted that either Callaghan or Jenkins (or both) would withdraw in favour of Healey as a unity figure.