The LibDems have written to the Prime Minister calling for the removal of non-domicile status for anyone who has been a resident in the UK for 10 years or more.
LibDem Shadow Chancellor Vince Cable says Conservative plans to hit all non-doms with a £25,000 flat rate annual tax are impractical and based on revenue assumptions that are too optimistic.
In the letter, Cable also called on Brown to release the findings of a Government inquiry into non-dom status. It was commissioned five years ago but has never been published.
The letter says: “A poll tax on non-doms would be prohibitive for the large number of non-domiciles of modest means, but would be a flea bite for the fat cats. The Tories’ charge would probably seem to Mr Abramovich not much more than a round of drinks at half time at Stamford Bridge.
“Our proposal seeks to deal with the abuse of the system, whereby people keep their privileged tax status for many years, and indeed pass it from one generation to the next.
“What really sticks in the throat is when people become active in political life, particularly as members of the House of Lords or as advisers to ministers, who turn out to have privileged tax positions despite having lived in Britain for many years.”