The closest Labour came to a succession plan was when Lange resigned and Geoffrey Palmer moved on to the ninth floor of the Beehive. There was certainly no plan in place though when Mike Moore shoved Palmer aside eight weeks out from the 1990 election.
And Jim Bolger never contemplated Jenny Shipley becoming the first female Prime Minister of the country when she did the numbers while he was downing aperitifs in Paris.
But Helen Clark was a mathematician compared to the rest of them. She carefully did the numbers when she rolled Mike Moore and was at it again when her own colleagues tried to shaft her a few years into her leadership. She hung on and became Prime Minister until the public did the numbers on her.
There was certainly no succession plan for Labour after her departure - Phil Goff, David Shearer and David Cunliffe would attest to that.
Similarly there's no succession plan for Teflon John Key, who has no intention of moving aside for anyone and the business leaders don't want him to at the moment either.
But there's one thing certain in politics, the day a leader's elected is the day his or her number's up!