Richest ever The Apprentice contestant was fired by Lord Sugar from the show

You would think that being the billionaire he is, Alan Sugar would be able to spot a true entrepreneur a mile off.

However, it would seem that even the Lord himself isn't infallible, as he has a track record of letting success stories slip through his fingers.

Over the years, the 75-year-old has hired and fired dozens of would-be business partners during The Apprentice process.

And despite many of them falling by the wayside, it's not just the winners who have made something of themselves since.

Luisa Zissman

The 35-year-old took part in the 2013 series, impressing Sugs right up until the very end, finishing as the runner-up after narrowly missing out to Leah Totton in the final.

BBC

However, despite not winning the competition, Zissman has gone on to become a huge success, amassing a fortune of around £1.5 million.

Saira Khan

She took part in the 2005 series, and like Zissman, she also came in second place overall.

But despite not quite doing enough to win the series, the mum-of-two has gone on to make an absolute packet.

A regular on Loose Women, and having been a contestant on Celebrity Big Brother, Khan is now said to be worth over £3m. Which ain't too bad, is it?

Ricky Martin (no, not that one)

Ricky was a contestant on season eight of The Apprentice a decade ago.

He made a name for himself on the show as a larger-than-life character who was an uber confident wrestler in his spare time, going by the name Ricky Hype.

Winning the show, he got some major investment from Lord Sugar and has grown his business to become a millionaire.

BBC

Katie Hopkins

I think the less said about her, the better really. But despite not winning the series back in 2006, withdrawing over private issues, she has made quite the name for herself, with some reports claiming she is worth over £2m.

Susie Ma

One of the biggest successes in the show's history is said to be Ma, who came third in 2011.

While not winning, the 33-year-old gained investment from Lord Sugar and now runs multi-million pound vegan skincare company Tropic Skincare.

According to The Times, the firm boasts annual sales of a whopping £22.5million, and she is said to be worth several million herself.

However, the most successful contestant of all time is none of these. That title goes to Alex Mills.

@alexmills/Twitter

In his early twenties, when he took part in series nine of the BBC show, Mills was fired by Lord Sugar following a pretty awful pitch for a new ready meal.

However, the entrepreneur, now in his thirties, didn't let it get him down. Nine years on from his Apprentice debut, Mills is now a multi-millionaire running successful insurance company Dynamo Cover. He is now said to have a net worth of around £16m.

Discussing his time on the show with The Times, Mills said he didn't regret losing Lord Sugar's investment, joking: "I tell you what, he isn’t having half my business for just 250 grand now."

I bet Sugs is kicking himself.