David Laws is hard at work on the mansion tax

An article in tomorrow's Guardian by Allegra Stratton reports that David Laws and Danny Alexander have been working on a Lib Dem document called Tax 2020:

Their mission is to detail where they want the party to be on tax in 2020 and then work back from there to see where they should be at each stage – now, in next year's budget, then the penultimate budget before the 2015 election and, of course, in the next parliament – be it in coalition with the Tories or maybe even Labour.

Stratton has seen part of the document and says that the two authors are close to arriving at a workable form of the mansion tax in the form of a mansion sales tax - a higher rate of capital gains tax on any profit made when selling a million-pound-plus house.

Other proposals include a cut to 5 per cent of the VAT rate on home improvements. Stratton also says that the Lib Dems will not oppose the abolition of the 50 per cent income tax rate when the Conservatives move to do it - according to one Lib Dem close to Clegg: "It's a sideshow."