This would give the party a distinctive policy going into the next election. With the proceeds of a land tax, they could abolish stamp duty and still have a lot of fiscal wriggle room allowing it to propose increasing the income tax threshold or spending more on certain public services. There's already work going on in Lib Dem circles on how to model a land tax and to find how much revenue it would raise.
Here’s the key section of the speech:
'It will be said that in a world of internationally mobile capital and people it is counterproductive to tax personal income and corporate profit to uncompetitive levels. That is right. But a progressive alternative is to shift the tax base to property, and land, which cannot run away, represents in Britain, an extreme concentration of wealth.’
At the next election, the Liberal Democrats will need a set of eye-catching policies to persuade the public that they remain a distinct political party after five years as the Conservatives’ junior coalition partners. Cable has made an early bid to make a land tax one of those.