They are also looking for the inclusion of measures to stop the rich avoiding Stamp Duty when they sell their properties, according to a report in The Independent published today.
Deputy prime minister Nick Clegg and other Liberal Democrat cabinet ministers will make their demands in behind-the-scenes talks with Osborne before the announcement on 21 March.
It is thought that, although the Chancellor is unlikely to introduce a mansion tax immediately, he may set up a review to look at raising the tax burden on the rich by targeting property assets rather than income.
Osborne is also likely to act on Stamp Duty, following several reports that the super rich regularly reduce Stamp Duty payments on their high value homes by putting their property in an offshore company, then trading the company rather than the house.
Other Liberal Democrat proposals include the introduction of a land tax and scrapping the 40% tax relief on pension contributions for higher-rate taxpayers.
They also want a crackdown on ‘non-domiciles’ – foreign residents living in Britain who do not pay tax on their overseas earnings.
To increase the pressure on Osborne, some Liberal Democrats plan to join Labour in trying to force the introduction of a mansion tax if it is not included in the Budget.
