The Mediterranean island of Malta is mired in a full-scale corruption scandal, much it surrounding the sale of residency-for-cash and throwing another spotlight on the general wrong-doing linked to the golden visa system in a number of countries.

The scandal reaches deep into the Maltese government cabinet and prime minister’s office, with the alleged formation of companies by some prominent individuals used to siphon off suspect money offshore.

The number of residence permits issued by Malta in 2016, the latest available year to be analysed, was the highest within the European Union in relation to the p...