The Deputy Prime Minister will accuse Ukip of stoking up anger then offering "fake solutions and dangerous fantasies".
In London, Mr Clegg will insist the LibDems are the only party that can fix Labour's mess, rein in the Tories and stand up to Nigel Farage's party.
Mr Clegg faces a tough fight to rally support when voters go to the ballot box this month, with polling at the weekend for the Euro election putting Ukip on 29%, Labour on 26%, the Conservatives on 23% and LibDems on 10%.
His party's battle to save English town hall seats will focus on the LibDems' record on freezing council tax and protecting key services.
The LibDems will unveil a dossier they claim sets out more than £500 million worth of "vanity projects" and "elaborate" expense claims racked up by Tory and Labour-run councils south of the Border.
Mr Clegg will say: "The local elections are different for us now, the Euros too. Bluntly, we are not the protest vote any more. But I have never wanted the Liberal Democrats to be just the 'none of the above' party.
"Everything I have done as leader has been about taking us on to the next stage: making the Liberal Democrats a serious party of government - national and local too.
"Ukip is Britain's protest party now and they are revelling in it. They think that all they need to do is stoke up people's anger, offering up fake solutions and dangerous fantasies - not least that idea that we could solve every problem Britain has in an instant, if only we left the EU.
"Well, the Liberal Democrats stand for something. We stand for fairer taxes. We stand for an economic rescue plan that isn't just built on cuts, but where we invest in roads, rail, business and all the things our communities need to thrive."
He urged people to support the LibDems, which he says is the only party that can "fix Labour's mess" at the poll on May 22, which coincides with the European elections.