The Deputy Prime Minister Nick Clegg has said that "people of very considerable personal wealth have got to make a bit of an extra contribution" towards what he describes as the "national effort". He will outline plans for his new wealth tax, which he suggests is necessary - at the Liberal Democrats' party conference next month.

In an interview with The Guardian newspaper, the Liberal Democrat leader said: "If we are going to ask people for more sacrifices over a longer period of time, a longer period of belt tightening as a country, then we just have to make sure that people see it is being done as fairly and as progressively as possible." This additional tax would be a "time-limited contribution", Clegg said, and would be on top of the Lib Dems' policy of a mansion tax on properties worth over £2m.

His comments will no doubt ruffle the Conservative coalition feathers, as the government has already announced the austerity programme of public spending cuts, including pay freezes in the public sector, will last for at least another two years until 2017. Clegg also outlined his commitment to crack down very hard on tax avoidance, and making sure that tax breaks don't go disproportionately to people at the very top". Which is slightly at odds with his government partners who, pushed to rush through cutting the top rate of income tax to 45% for the wealthy in the Budget.

Well, as they say watch this space. It will be interesting to see how Clegg and Cameron address this big elephant in the room.

Written and presented by Ann Salter