And Mr Clegg, whose own party was eviscerated at the same election, said it is a 'travesty' the anti-European Union party were able to take 12 per cent of the voting share and only have one voice in parliament.
The Liberal Democrats got approximately 2.4m votes in 2015 and walked away with eight seats after losing 49 taking just 7.9 per cent of the vote.
But now, ahead of the Stoke by-election on February 23, in which new Ukip leader Paul Nuttall is standing, Mr Clegg says the fact Douglas Carswell is the only MP will lead to a huge backlash at the polls.
Nick Clegg says Ukip will only garner more support ahead of next elections
I think there is a permanent role for a party like Ukip in British politics
He said: "I think there is a permanent role for a party like Ukip in British politics and I might surprise you and say that that's exactly how it should be.
"Look, pretty much across the democratic world now there is a chunk of public opinion, it tends to be older, that is very uncomfortable with modernity and is very uncomfortable with contemporary life that wants to turn the clock back, that wants to return to the most restful simplicities of the past.
"And you see parties catering to that nostalgia to simplify things and slow things down. You see parties responding to that.
"I think the resonance of Ukip isn't just on the European issue, I think the resonance of Ukip speaks to a longing amongst a significant number of our fellow citizens to kind of slow stuff down and can return to what I would regard as an unrealistic sepia tinted past; but nonetheless that's a very strong instinct and I think it is an absolute travesty that four million people voted for Ukip at the last election and all they got was Douglas Carswell.
Clegg addressed an audience at University College London
"That is a very poor return on that vote but it is a serious point.
"If you brush people who feel like that under the carpet and only give them one MP don't be surprised that when they're next asked to vote they will be even angrier, not everybody, but I suspect a fair number of Brexit voters will say 'to hell with you, you asked me last time what my opinion was and you just seemed to ignore it altogether, so next time you will have to jolly well listen to me’.”
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Mr Clegg has been visiting a number of universities Nigel Farage: Man of many faces Fri, May 8, 2015
UKIP leader Nigel Farage is certainly animated. We've put together his best and worst expressions!
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The many faces of Nigel Farage
The controversial 50-year-old has been doing the rounds of universities trying to win support for his former employer, the undemocratic EU, insisting he will continue to be a "remoaner."
Mr Clegg told a captive audience at University College London that he believes UK democracy has been "paralysed" and even suggested that Jeremy Corbyn's leadership of the Labour party was "not even a good work in progress".
He added: "Ukip should play a continued role as a voice for those people who kind of want to turn their backs on the modern world and I think it's an outrage, an outrage that they are as under represented as they are in Westminster. Not that I agree with a thing they say before they get wildly misinterpreted.
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