Speaking exclusively to City A.M., the billionaire entrepreneur said: "I think Jeremy Corbyn is totally useless and he’s destroyed the Labour party. It’s finished. It’s dead. They’ve got to find a new leader.
"They need to kick him out but he’s so belligerent he won’t go."
The Amshold boss quit the Labour party in 2015 after slamming its "negative business policies" and "anti-enterprise concepts".
Online retailers should pay more in business rates
"Business rates are ridiculously high. There should be a holiday for companies that are under a certain turnover. Amazon is the biggest retailer in this country... but they are putting other shops out of business. So I would impose some sort of tax on online retailers because they are the ones killing the small shops off."
Stamp duty effects are "a slap in the face" for government
Sugar, who was appointed the government's enterprise tsar in May last year, also hit out at the previous government's "punitive" stamp duty hikes.
"There have been some very silly moves by the prior government as far as stamp duty is concerned. It was really a cosmetic thing that they imposed ridiculously high stamp duty rates on expensive properties thinking it’s going to bring in revenue. Instead it’s had a reverse effect and all those big buyers from overseas have stopped coming here because of that.
"It was like they said, 'let’s make the rich pay' but in fact, it’s come back and slapped them in the face. I hope they see sense and bring the stamp duty down to the same level as it was before."
"No one understands Brexit"
Speaking about Brexit's impact on business, Sugar said: "No one understands what the effects of Brexit will be, including the government. The most important thing is to make sure that we are still able to have free movement of trade throughout the whole of European Union.
"We’ve got a good chance of that simply because we are one of the biggest consumers in Europe. I can’t see them all ganging up against us and enforcing tariffs on us on shipping stuff within Europe because it’ll be reciprocal and we’re a big consumer market."
Sugar added that British people were "totally wrong" to vote for Brexit.
"I’m not positive about Brexit, absolutely not but I’m pragmatic because we live in a democracy where people voted for it. The people were wrong, totally wrong to vote for it. Their vote was simply a vote against the government because they didn’t like the climate and the conditions in the marketplace."
He went on to liken the vote to US President Donald Trump's election win.
"It’s [the Brexit vote] very similar to what happened in America to Donald Trump. The American people were also fed up with the conditions in the marketplace and he went out and ticked all the boxes about what everyone was fed up about and people went and voted for him."
Sugar's new business
Sugar has invested £250,000 in Ridiculously Rich by Alana whose products are manufactured and distributed from a site in Cross Hands, West Wales. The baking business will offer people the chance to become business owners by applying to be a regional brand ambassador, representing the business at shows and venues in the UK.
"Alana won the Apprentice, and quite rightly so, for her business acumen. I have admiration for how she started this business at the back of her mum and dad’s kitchen. Someone making money like that from scratch definitely encouraged me to choose her as my business partner," Sugar said.
Speaking about working with Lord Sugar, Spencer said: "It was very daunting when I was told I won but it’s been straightforward since. The good thing about Lord Sugar is he’s very to the point so there’s no flowering anything up.
"The goal is to become a leading player in the luxury cake market – that’s my dream. I want to make many more ranges."