From non-job to key job - Why there's so much at stake in the election for Rayner's replacement.

It was once regarded as a non-job. But the election for Angela Rayner's successor as deputy Labour leader threatens to plunge the party into a new civil war.

The contest, whenever it happens, could potentially be the most divisive since the bitter left-right split when Tony Benn challenged the incumbent, Denis Healey, in 1981.

It was the year of the launch of the breakaway SDP by the "Gang of Four" - Roy Jenkins, David Owen, Shirley Williams and Bill Rodgers - and defections by several more Labour MPs.

There was speculation that if Benn - then in his hard-left phase before he became a national treasure in his latter years - there would be far more defections to the SDP.

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This time, however, the threat of defections by Labour MPs comes not from the centre,