Nick Clegg insisted the coalition was already proving doubters wrong today as he took temporary charge of the reigns in Downing Street.
The Deputy Prime Minister said the Government was proving to be "radical and reforming" rather than the "insipid mush" many had predicted.
Speaking at a Town Hall-style event hosted by MSN.com in London, Mr Clegg was asked how he thought the coalition had performed in its first 100 days in power.
"I think many people felt that a coalition government by definition would be some sort of insipid mush, where different parties sort of haggle constantly with each other until they produce some lowest common denominator policies that do not really make a difference," he said.
"Actually, what we are finding out after after 100 days we are being accused of doing exactly the reverse, which is doing things too quickly, too fast, too radical, too reforming.
"I think that is a sign of a government - whether you agree with it or not - that has got a strong sense of purpose."
Asked if he imagined a few months ago that he would be taking the helm of government, the Liberal Democrat leader replied bluntly: "No."
He stressed that Prime Minister David Cameron was still officially running the country despite being on holiday.
"I'm holding the fort for a couple of weeks and I'm doing so in the spirit of partnership," Mr Clegg added.
Mr Clegg claimed there was "light at the end of the tunnel" as he defended the Government's efforts to repair the economy.
He said it would take the fixed five year duration of the Government to "sort things out" but added: "I think there is light at the end of the tunnel.
"There's so much gloomy news out around, I think there are some glimmers of better news.
"I hope when the five years are up people will see that we have taken difficult decisions, some controversial ones, some unpopular ones, but we have done it for the right reasons in order to get the economy right, get growth going again and give people a sense of hope for the future again."
He said the measures taken to bring down the deficit could not be "ducked" due to the economic turmoil in Europe and the pressure exerted by the markets.
It was also "morally wrong" to continue to build up debt.
"There's nothing fair or socially just about handing on debt from one generation to the next.
"Someone had to draw a line and say 'no, we're going to sort this out' because you can't create growth, you can't create a fair economy on the sands of debt."
One of the potential fault lines in the coalition is over the replacement of the Trident nuclear deterrent.
Mr Clegg said his views, opposing a like-for-like replacement, were well known.
"It's going to be difficult for someone who is going to receive less housing benefit because of the changes we are introducing to understand why, at the same time, we should spend huge, huge amounts of money in a hurry on replacing Trident in full."
Mr Clegg answered questions submitted over the internet on Twitter and email during the wide-ranging session.
He acknowledged that ministers may have failed to spell out the reasons behind the tough tax and spending measures contained in the Budget and acknowledged there had been lengthy deliberations within Government before the VAT hike was agreed.
The Deputy Prime Minister said: "I can assure you in lengthy, lengthy meetings we looked at so many different ways of trying to avoid this or do something different."
He added: "The Budget we produced, and I think it's one of the things that maybe we didn't communicate enough, was a very different budget to previous budgets.
"It wasn't a budget for six months, it wasn't a budget for a year, it was a budget for a parliament which included, yes, this VAT move at the beginning.
"It's not something we relished, far from it. It's not a comfortable decision to have to take at all.
"But I think if you put it in the context of all the other things we are going to do, we're trying to make this package as fair as we can and trying to make sure that we're not hitting frontline public services harder than would have to be the case if we don't do something like (raise) VAT."
On immigration, Mr Clegg said there was no "magic number" for the amount of migrants allowed to enter the UK.
The Government plans a cap on the number of non-European immigrants but Mr Clegg said a major focus should be placed on building confidence in the system.
"I don't think there's any magic number.
"I think it's a combination of things. I think you, as the Government has published in our coalition agreement, you put an upper limit to the overall number of people who come in from outside the European Union but much more important than that you've got to make sure that the immigration system has people's confidence and has people's trust."Reuse content