The evolution of Labour’s leadership election system owes as much to politics as to democracy. In 1979, Tony Benn’s supporters, led by Michael Meacher, tried unsuccessfully to introduce an electoral college system through which the leadership would be elected by party activists, union block votes and MPs. They were temporarily defeated. Benn’s diary reads: ‘We’ll come back next year and put it right.’ It was a ‘heads I win, tails you lose’ view of democracy.

In 1981 they succeeded, changing the system of election by secret ballot of MPs, which had served the party since 1906, when Labour’s parliamentary leader was the ‘chairman’ of a small trade union ‘pressure group’. Only in 1922 was the chairman renamed ‘leader of the parliamentary Labour party’, and not until 1978 that the role was renamed ‘leader of the Labour party’.

Labour’s MPs proved unwilling to elect Benn their leader, so his followers formulated an electoral system to guarantee a Benn victory. It was a mere spanner that would ultimately destabilise their machinations – Benn’s rejection by Bristol East at the 1983 election, making him ineligible to stand in the leadership election which saw Michael Foot’s protégé, Neil Kinnock, defeat the Gaitskellite Roy Hattersley.

During 1979 to 1981, Frank Chapple, leader of the moderate EETPU electricians union, and the MPs David Owen, George Robertson and Frank Field, were almost alone in advocating an alternative ‘one member, one vote’ system, whereby the party membership would elect the leadership by postal ballot. The Bennites claimed OMOV would give undue influence to the media. Chapple reminded them that these were the arguments used against widening the franchise in South Africa. Owen famously warned Labour conference: ‘The day this system is used to elect a prime minister … these procedures will be shown to be totally undemocratic.’

Union leaders were reluctant to surrender their block votes, and despite Kinnock’s post-1983 conversion to OMOV it was not until 1993 that John Smith – helped by a famous speech that secured John Prescott the deputy leadership in 1994 – secured change. Even then it was not pure OMOV, as Chapple advocated, but OMOV within a rebalanced electoral college (33 per cent each to MPs, members and unions). This is essentially the system we have today, in which an MP’s vote is worth more than an ordinary member’s. But it is ordinary members who vote in their section, not just activists, and each union must conduct a secret ballot.

Since 1994 the nominations threshold has increased – to 12.5 per cent of MPs – but little else has changed. The process will last a minimum of seven weeks, with the first being a nomination period. After a period for hustings, in which Gordon Brown will participate along with the deputy contenders even if he is the only leadership candidate to secure sufficient nominations to run (though he would face no vote), there will be a fortnight for balloting with voting by preference. The winner requires 50 per cent of the overall votes.

Uniquely, this contest is likely to be dominated by personality over policy. Virtually every previous leadership battle, apart from Clement Attlee’s defeat of Herbert Morrison and Arthur Greenwood in 1935, has been a battle between right and left. Until Foot’s defeat of Denis Healey in 1980, the right usually won (apart from when the centrist Harold Wilson beat George Brown and Jim Callaghan in 1963). Moreover, Gordon Brown lacks any credible challenger. Only Morrison in 1951 enjoyed similar stature – and Attlee jealously held onto the leadership until 1955 to give rivals time to emerge.

Until Nye Bevan unsuccessfully contested Morrison in 1952, the deputy role had been appointed uncontested by the leader. Its position was almost informal until Labour’s constitution was amended in 1953 to give the deputy leader a formal seat on the party’s NEC, following Morrison’s ejection by Bevanites the previous year. It was absorbed into the familiar right-left leadership battles, becoming the consolation prize for defeated left-wingers until 1980, and defeated right-wingers until 1992, when Margaret Becket recaptured it for the left. It was John Prescott who sought to redefine it as a campaigning ‘party’ role, standing unsuccessfully on this platform against Hattersley in 1988. It will be interesting to see what today’s candidates want to make of it.