Clegg said he would not "flinch" in the face of criticism of his leadership from within his Liberal Democrat junior coalition partners after a much-mocked apology for a policy u-turn on university tuition fees.

 

As he prepares to address his party's annual conference in Brighton on Wednesday, Clegg tried to restore his reputation by insisting the coalition will not make further public spending cuts "on the backs of the poor".

 

He pledged that the Lib Dems would not agree to any more spending cuts unless Prime Minister David Cameron's Conservatives agree to some form of "wealth tax".

 

Clegg said the apology for breaking a promise made by his centrist party before the 2010 election to block university fee increases had been necessary because the u-turn had "obscured" all the "good things" the party had done.

 

His apology has been lampooned and set to music in what has become a YouTube hit which has entered the British download charts -- with Clegg's agreement.

 

He said that with Britain's economy taking longer to recover from the slump than expected, he would seek again to persuade the Conservatives to introduce a tax targeting the highest earners.

 

"The vast majority of people in this country would find it wholly unacceptable if further fiscal austerity was implemented on the backs of the poor," Clegg told BBC TV.

 

"I'm not saying something as big as welfare is immune from further savings but I'm saying that the burden has to be spread fairly."

 

He said he remained a strong supporter of the introduction of a so-called "mansion tax" targeting the owners of the most expensive homes.

 

"I believe in a mansion tax," he said. "I think many people of considerable wealth in this country want to pay."

 

He admitted "we have not yet managed to persuade the Conservatives", but insisted "there are an increasing number of Conservatives who understand the merits of having more tax on higher value properties so you can lower tax on effort and work".

 

Cameron's party opposes the introduction of a wealth tax, saying it would be unfair to levy it after a home had been purchased.

 

But Clegg said he believed there was "a very considerable chance" to persuade the Conservatives "to make sure the top (earners) pay more tax".

 

Clegg made his video apology for the student fees as a ratings poll by Ipsos Mori showed voter satisfaction at its lowest level ever, dropping from 31 percent to 23 percent.

 

He is also facing low popularity ratings within his own party and there are rumours of a possible challenge to his leadership from one of the Lib Dems' few stars, such as business minister Vince Cable.

 

Clegg dismissed suggestions he would stand down before the next election which is due in three years' time.

 

"I am not going to flinch, I don't think you should flinch when you are halfway through a journey when no-one can possibly predict what the economic and political circumstances are going to be in 2015," he said.

 

The Lib Dems kick off the traditional autumn party conference season, followed by the main opposition Labour Party and then the Conservatives.