The UK Treasury has been forced to admit it cannot put overall figures on how many people claim or qualify for non-domicile tax status, nor can it quantify how much tax has been lost through the controversial loophole or its benefits to the economy.

Last month Vince Cable, the Liberal Democrat shadow chancellor, tabled written questions demanding details about the prevalence of non-domicile tax status use in the UK in an effort to turn up the heat over the issue, and he has now received the Treasury's responses.