The index ranks countries from zero to ten on the basis of answers to 17 surveys and assessments. Higher scores signify lower levels of corruption, which the organisation defines as 'the abuse of entrusted power for private gain'. New Zealand’s score this year is 9.5, while Finland and Denmark were given a mark of 9.4.

Last year Finland got 9.2 points and came in fourth, although Transparency International warns that a country’s score cannot be compared to its score in a previous year.

Eurozone countries hit by the debt crisis were among the lowest scoring European Union countries, partly because of what Transparency International calls their failure to deal with bribery and tax evasion.

Finland has seen heightened debate about corruption in recent years following several election funding scandals.