In the final week of the New Zealand election campaign, an unlikely thing happened. Faced with the prospect of winning its first parliamentary majority since 1897, Labour took a gamble.

Finance Minister Grant Robertson made a direct appeal to traditional supporters of the centre-right National Party, particularly those fans of former prime minister John Key, a popular leader who won three consecutive elections and oversaw a turnaround in the New Zealand economy. National, Robertson said, was no longer the party of Key and his finance minister and successor Bill English. It was an unstable rabble. If you want stability and sensible economic management, so went the pitch, vote for Labour.