Apprentice star and peer Lord Sugar has quit the Labour Party - blaming their "negative business policies" and anti-enterprise approach.
The entrepreneur delivered a damning assessment of the party's business credentials under Ed Miliband's leadership as he revealed he had lost confidence in Labour during the last 12 months.
Lord Sugar, who will continue to serve as an independent crossbench peer, added he made his decision at the start of the year and would have resigned even if Labour had won the election.
He was initially appointed a peer by the previous Labour administration in 2009 but signalled he had sensed a policy shift back towards the principles of "Old Labour" under Mr Miliband - particularly in relation to business.
The peer said he informed the party of his decision on Friday and kept his intentions quiet rather than use them to "possibly damage" Labour's election chances.
But Lord Sugar has made his decision public just days after Labour suffered its most damaging election defeat in a generation.
The party's election campaign under Mr Miliband has also been criticised by party figures in recent days for lacking an economic policy.
The manifesto listed the first task of a Labour government was to change the economy so that it "works for all of Britain's businesses and working people", with policies focusing on zero hours contracts, increasing the minimum wage and cutting rates for small businesses.
In a statement, Lord Sugar said his resignation was accepted as the party had been "aware of my disillusionment for some time".
He said: "In the past year I found myself losing confidence in the party due to their negative business policies and the general anti-enterprise concepts they were considering if they were to be elected.
"I expressed this to the most senior figures in the party several times."
He continued: "By the start of this year, I had made my decision to resign from the party whatever the outcome of the General Election.
"However, I am a loyal person and rather than use my decision to possibly damage the party's chances in the election, I decided, as a relatively high-profile individual, to keep my intentions quiet for the duration of the campaign."
Lord Sugar said he had declined hundreds of media requests to talk about the party's proposed policies, particularly in relation to business.
He said: "I have no wish to stick the boot into the party.
"There are many good people in Labour working hard every day to serve the public and I wish them all the best of luck.
"I am grateful for all the experiences being a member of Labour has brought me."
He added he will continue in the Lords in order to represent the interests of business and enterprise in the UK.
During his maiden speech in the Lords, the peer confronted criticism of his appointment as an "enterprise champion" by Gordon Brown's government.
He also made reference to his successful BBC show, telling peers in 2009: "I am the new boy on the block. In your Lordships' House I am certainly the apprentice.''
The 10 richest reality stars
Lord Sugar quits 'negative' Labour Party
Klass is worth £11 million. She was an early winner in the pop competition phenomenon. The classical musician took part in Popstars in 2001, where she took the title as a member of Hear’Say. The win brought her £1 million immediately, but the band only lasted two years. She was snapped up after the band split, but had limited success as a solo pop artist.
Her second big break, however, came when she appeared in I’m A Celebrity Get Me Out of Here in 2006 and took an array of small bikinis with her. She subsequently balanced modelling with a return to classical music. And since then had delved into an incredible array of enterprises, ranging from designing a range of baby clothes for Mothercare to presenting Loose Women and hosting a show on Classic FM.
Lewis is worth £13 million. She became the third winner of the X-Factor in 2006, and is currently the second richest act to emerge from the show. She has now produced four studio albums, and sold 20 million copies. Some of her money-making potential may lie in the fact that she was mentored for seven years by Simon Cowell.
She hasn’t made a vast amount of money in projects beyond her music, although she has a line of accessories, a very successful perfume, and is a face of The Body Shop. She also made her film debut this year in Walking on Sunshine.
The band is worth £14 Million (each). It’s no surprise to see this global phenomenon on the list, and it’s worth remembering that one of the reasons they are not higher up it is that they only shot to fame on X Factor in 2010. The boys famously auditioned as solo acts, but made the cut after being brought together by Simon Cowell as a supergroup.
Their money-making comes partly through the music, including selling 45 million records, £270 million of tour ticket sales, and a box office smash hit movie. They have also taken merchandise to the next level. Their range includes bedding, lipstick, perfume, hats, bags, dresses, jewellery, shoes, a onesie, glasses, dolls, shot glasses, nail varnish, cushions, headphones and mobile phone covers - and every item is an enormous hit because they have generated one of the most loyal fan bases in pop’s living memory.
Hudson is worth £15 million, This is an amazing result for someone who came seventh on a reality show talent competition. However, Hudson raised her profile enough to catch the eye of the moguls casting the hit movie Dreamgirls - earning herself an Oscar for Best Supporting Acress - and kickstarting a lucrative film career.
She has since released three albums, and landed a WeightWatchers job, all of which have helped add to the coffers and bring her into seventh place.
The first ever winner of American Idol in 2002 is worth £16 million. She has now released six best-selling albums and completed three world tours. The majority of her wealth is said to come from record sales - of which she has sold 20 million. She’s expecting to release another album at the beginning of next year, so she’s unlikely to run short of cash any time soon.
The artist now known as Cheryl Fernandez-Versini is worth £16 million. She was part of the reality girl group Girls Aloud, which won ITV’s Pop Stars: The Rivals in 2002. Within the group she amassed £6 million after selling four million albums over seven years, but the rest of her fortune has been built up through an array of projects since.
Her solo career has included three hit albums, modelling contacts with the likes of L’Oreal and Coca-Cola Zero, judging on The X Factor (and a very brief stint on the US version of the show), and a signature perfume. She is said to have so much faith in the strength of her recent marriage that she refused to sign a pre-nuptial agreement to protect her cash
Boyle is worth £22 million, and is perhaps the ultimate reality TV success story. From the moment the 53-year-old blew the audience away during her Britain’s Got Talent audition in 2009, her unique talents were set to transform her life. In the end she only came second on the show, but was snapped up by Simon Cowell’s record label and was immediately put to work.
Despite having relatively fragile health - which has meant a less full-on promotional whirl than the One Direction boys, she has released four albums, and sold more than 19 million copies. She has also embarked on a tour, and has performed at the opening ceremony of the Commonwealth Games and for Pope Benedict XVI. It is no surprise that her story was turned into a musical, and the rights bought to turn it into a film.
Roots (whose real name is actually Keith Valentine Graham Bilal Musa) is worth £30 million. He took his jerk sauce to a trade show in 2006, where he was spotted by a BBC producer who suggested he appeared on Dragon’s Den.
In 2007 he blew the dragons away (despite getting his maths very wrong when calculating how much sauce was on order), and won over Peter Jones and Richard Fairleigh. Now it’s not just his jerk sauce that is stocked in supermarkets - but a vast range of pizzas, sauces, ready meals and even cakes. He has also produced best-selling cook books and a BBC series, and tours the speaking circuit.
Hilton is worth £36 million, and is the first on this list to be famous for nothing in particular - generally known as being a Hilton hotels heir and a socialite. However, since she appeared on her own reality TV show, The Simple Life, with Nicole Ritchie, she has made a fortune through a huge number of ventures. Reality TV has been good to her, with her BFF reality show franchise and The World According to Paris. Telling her story has also made her rich - with two autobiographies and a documentary on the subject. She has appeared in several films and TV dramas, and released an album.
However, she has also shown an incredible ability to sell products. She has her own fashion lines - including one for dogs, more than ten fragrances, jewellery designs, hair extensions, shampoos, hair vitamins, shoes, an app, sunglasses, and a chain of accessory shops.
The top position on the list goes to Kardashian West, who is worth £39 million. She’s another ‘socialite’ who came to the attention of TV producers in 2007 through a leaked sex tape. This lead to Keeping Up With The Kardashians - which has since spawned nine series and four spin offs. This only explains a fraction of her wealth, however, because Kim Kardashian’s ability to cash in on fame is unprecedented.
Her enormous number of endorsements include perfume, trainers, diet products, nail polish, jewellery, watches, a cupcake mix, lollipops, Carls Jr fast food, a gaming app, candles, laser hair-removal, fake tan, lipgloss, and swimwear. The family owns a chain of boutiques, and a clothing line called the Kardashian Kollection. Even her wedding in 2011 was said to have made her £6 million.