Lord Sugar has signed a new three-year deal with the BBC to stay on The Apprentice.

The billionaire was already contracted to do the 20th series of the show next year, but says he has signed to do three more series, taking him into his 80s.

Lord Sugar, 77, revealed the deal in a new interview with the BBC’s Amol Rajan.

Now in its 19th series, criticism of The Apprentice falls “like water off a duck’s back” these days, he said.

He puts money into the winner’s business, investing £250,000 in exchange for half of their company.

And he says he’s “absolutely” proud of the programme’s legacy.

“Listen, when I took the job on of The Apprentice, I was already a multi-millionaire.

“I didn’t do it for the money.”

In the wide-ranging BBC interview, Lord Sugar reflects on his life and career, and also discusses President – and original US Apprentice star – Donald Trump, former contestant Katie Hopkins, and the “disaster” of Brexit.

Known for his cantankerous, no-nonsense business dealings and his “you’re fired/hired” catchphrase, Lord Sugar insists his on-screen persona is how he is in real life.

“That is me mate, I’m promising you,” he tells Rajan in the BBC Two interview.

“I have sat on the production line, I’ve made stuff, I’ve packed boxes, I’ve loaded lorries, I’ve delivered, I’ve collected money. Every single facet of business, I have done all of it.

“So when I got that Apprentice gig, sitting there listening to these budding entrepreneurs, I was able to interrogate them properly.”

Lord Sugar is arguably one of the UK’s most famous rags-to-riches stories.

After failing an aptitude test with tech company IBM as a young man in Hackney, east London, he started selling car aerials from a van, and later transistor radios.

He launched his own electronics and technology company Amstrad in 1968, making home computers and satellite dishes for Sky, then through property investments and other ventures went on to become one of the country’s richest men.

Alan Sugar was approached by the BBC about making a UK version of a popular business-based entertainment show in the mid-noughties, towards the end of his challenging tenure as chair and owner of Tottenham Hotspur Football Club.

But why did he say yes?

“Because Donald Trump in America did The Apprentice first of all – and I have got a home in America, in Florida, and all the people were telling my wife, ‘This is the greatest TV show ever’,” he explains.

“So I knew of it.”

He’s reticent to talk about the now US president, saying “there’s no comparison” between himself and the other former face of The Apprentice.

“He’s nothing like me and I’m nothing like him,” he says. “But the point is that what he’s doing is very, very unusual.”

Last month, Trump clashed with Ukraine’s president, Volodymyr Zelensky, in a furious exchange at the White House. “Unbelievable,” says Lord Sugar.

“There are certain things in life that I didn’t think I’d ever experience. One was Brexit, which is the biggest tragedy. [Then] you’ve got a leader of a country, of America, publicly having a slanging match with someone else. It’s just not right.

“By all means have a slanging match behind closed doors, but not publicly.”

He describes the very public incident as “humiliating for Zelensky” while showing Trump’s “temper”.

“It’s not statesmanlike, is it?”

He goes on: “He may have done himself a favour amongst some of the Americans that backed him, but I don’t think he did himself a favour [in front of the rest of the world], quite honestly.”

Asked how he would get the best out of Trump in negotations, he replies: “The only way you can deal with him is to not disagree with him.

“End of.”

Always forthright with his opinions, Lord Sugar made recent headlines by airing his views on topics including working from home, telling workers to “get their bums back to the office”.

He’s also shared his thoughts on female football commentators, Brexit and Boris Johnson, to name a few subjects.

Speaking in the House of Lords in 2018, Lord Sugar said Brexit campaigners, such as Tory politicians Johnson and Michael Gove, should be prosecuted for “the £350m lie they put on the red bus”.

“Brexit was a total, absolute disaster,” he tells Rajan. “And anybody who says it’s not is deluded.

“That has changed so many things.”

Despite calling for him to be jailed, a year later Lord Sugar backed Johnson as the next prime minister in order to “stop [Jeremy] Corbyn getting into power”.

He believes rejoining the EU is the answer to getting the UK growing again.

“I’ve never met [Prime Minister Sir Keir] Starmer, but if I ever did I would ask him, is it possible? What mechanism would it take to effectively get down on your bended knees and beg to be allowed back in again?

“That’s what I would do. If I was in charge, I would beg to get back in again.”

Over the years, several contestants have quit the Bafta TV Award-winning show, billed as “Britain’s toughest job interview”, before being fired or hired, including in the latest series.

“I realised they’re going to jump before they’re pushed, in some cases,” says Lord Sugar.

He picks out one famous former contestant, Katie Hopkins, as someone who could have got the job had she not walked first.

“Remember her?” asks Lord Sugar. “Ratchet jaws, rent-a-mouth.”

Hopkins, nowadays a media personality and right-wing political commentator/provocateur, appeared on series three in 2007 but left the show despite being offered a place in the final because she could not commit to a potential move to London.

“I was about to say, ‘Well, I’ll hire you’. And she says, ‘No, actually, I don’t want to do it’. So she left,” he remembers.

“She was good. She was the best of that crew. No question of it.”

Reflecting on the show, he believes some contestants now apply to go on The Apprentice to achieve social media fame, rather than for the chance to work with him.

“I spot them straight away, so that’s why they never become the winners,” he says.

“So they’re out, but they’re part and parcel of the entertainment package of the programme.”

Amol Rajan Interviews: Alan Sugar is available on iPlayer and airs on BBC Two at 19:00 GMT on Thursday, 20 March.