Mr Meacher was keen to stress the importance of having a debate within the Labour Party.This is wrong on several levels.
"The Labour party, throughout the hundred years of its history, has elected its leader every single time, except in 1931, which was very exceptional circumstances," he said.
Prior to 1922 the position was "Chairman of the Parliamentary Labour Party", which was something of a different position. I forget exactly how many contests there were for the post (the first one in 1906 saw Keir Hardie elected with a one vote majority over David Shackleton), but a glance at David Marquand's Ramsay MacDonald suggests that the 1907 election was unopposed (Hardie stood down under pressure, Shackleton declined to run and Henderson was elected - page 102). Wikipedia so far doesn't list any contests before 1922 - see Wikipedia: Category:Labour Party (UK) leadership elections.
1922 saw the position redefined as "Leader of the Labour Party" and "Chairman of the Parliamentary Labour Party", although the latter post eventually became separate. Even then there were unopposed elections - 1931 was not as dramatic as Meacher makes out, for Ramsay MacDonald was still a member of the Labour Party at the point when Arthur Henderson became leader. As the leader was elected by Labour MPs only, it would have been entirely possible to hold a ballot. Instead for some time as the Second Labour Government limped to its resignation it had been clear that MacDonald's leadership was coming to an end and Henderson was the only likely successor - shades of this year.
Then in 1931/32 the leadership was again elected without a contest. Henderson lost his seat, together without about 80% of Labour MPs, in the 1931 election but remained leader for another year. In the interim George Lansbury, the one former Cabinet Minister to survive, was elected to head the Parliamentary Party - without a contest. When Henderson stepped down in 1932 (to focus on the Disarmament Conference), Lansbury was elected full leader without a contest.
Then in 1935 when Lansbury insisted on resigning, even in spite of a unanimous resolution urging him to stay passed by a meeting of the Parliamentary Labour Party, Clement Attlee was elected as leader unopposed. True he was regarded as a stop-gap until after the forthcoming general election (and he did indeed face a contest later that year), but he was still elected unopposed.
Plus at various times throughout Labour's history the leadership has been elected automatically at the start of each Parliament or even every year (when in Opposition). Numerous leaders have been re-elected unopposed - did Michael Meacher not notice these?
So ignore sweeping statements that unopposed leadership elections are alien to Labour - after all one produced their longest serving leader ever.