The thought of an election in one country being decided by the fate of 500 rich people in another might seem absurd. But such is the controversy around a wealth tax these days that this is just what could happen in Norway, itself one of Europe’s richest countries.

Hundreds of the Scandinavian country’s business people and entrepreneurs have fled the icy north for Switzerland in recent years, largely in protest at changes to Norway’s long-standing wealth tax made by the centre-left government in Oslo. Local bank DNB estimates more than 500 Norwegians with at least SFr2mn ($2.5mn) are in Switzerland.

They are now at the heart of the centre-right’s attempts to retake power in Norway. “Taxation is one of the big dividing issues between the left and right sides, especially the wealth tax,” says Erna Solberg, former prime minister and leader of the Conservatives.