In a defiant message, Mr Clegg will tell the party’s activists that the Liberal Democrats will do “better than anyone thinks” on May 7, despite single-digit opinion poll ratings.
The Deputy Prime Minister will use his keynote speech at the Liberal Democrat spring conference to insist that the party “can and will win” in areas where it can mount a strong campaign on the doorstep.
Hailing the party’s “incredible resilience”, he will say: “It is because of our resilience that Britain has a strong, stable Government and a strong, stable recovery.
“It is because of our resilience that we have been able to achieve incredible things. And it is because of that resilience that we will defy the odds and win again this May.
“So when people tell you we can’t, tell them where to go. I have a message for all those who are writing us off once again: the Liberal Democrats are here to stay.”
Mr Clegg, who asked anyone who could give a perfect answer to explain the party’s poll decline to “stick it on a postcard and send it in” yesterday, will insist that the Lib Dems can defy the odds in the 56 seats they currently hold.
“I’ve heard the predictions. I’ve seen the polls. But let me tell you this: we will do so much better than anyone thinks,” he will say.
“In those seats where we are out in force, making our case loudly and proudly, we are the ones making the weather. I’ve seen it for myself in Liberal Democrat seats across the country.
“We are showing that with hard work, strong local campaign teams and a record of delivering for people in national and local government, we can and will win.”
Appealing to wavering voters, he will say: “If you are thinking of voting Conservative but are worried that they won’t be fair - don’t do it. If you are thinking of voting Labour but are worried they will ruin the economy - don’t do it.
“If you think a vote for Ukip, or the Greens, or the SNP is harmless - it isn’t.”
At the conference in Liverpool yesterday, Mr Clegg said the final significant decisions of the current coalition Government had already been taken, with negotiations over Wednesday’s Budget almost finalised.
He will tell activists that the fact the coalition has lasted the full term of the parliament meant the Lib Dems had “changed the political landscape forever”.
Mr Clegg will say: “Five years ago we were told a hung parliament would be a disaster for Britain.
“We were told that without a clear majority for one of the old establishment parties, Britain would collapse into chaos. We proved them wrong.
“We broke the stranglehold of the two old parties and proved that coalition can be strong, stable and successful.
“We proved that the give and take of different parties working together can be a very British way of getting things done.
“We challenged the power of the vested interests on the left and right of the British establishment and we felt their wrath in return. And we are still standing.”