Venture capitalists on TV shows like Shark Tank and Dragons' Den may think they're shrewd enough to spot a lucrative business opportunity when it's pitched right in front of their faces, but they don't always get it right and, every so often, the rejects get the last laugh. Here are 18 ideas TV panels of angel investors turned down that defied expectations and went on to become major successes.

Jake Epstein and Joe Lemay's endlessly resuable notebook uploads notes to the cloud and can be microwaved to erase data. Good idea? The investors on the most recent season finale of ABC's Shark Tank in the US didn't think so, which is their loss.

A resounding success, the gizmo has so far generated $10 million (£7.9m) in revenue and was an Amazon's top-selling notebook in November 2016.

Across the pond, James Nash fared just as badly when he pitched his Cup-a-wine idea to the bemused investors on season seven (2009) of BBC's Dragons' Den show.

Laughed off as “tacky”, the invention was picked up by major chain M&S later in 2009, marketed as Le Froglet and has since become a familiar sight at picnics and on commuter journeys in the UK.

American entrepreneur James Martin presented a similar idea to the venture capitalists on ABC's Shark Tank twice in seasons two (2011) and three (2012) but walked away without a deal both times.

Described by Shark Kevin O'Leary as “the one that got away”, Martin has made a huge success of his wine in a glass concept, turning over $14 million (£11.1m) a year by 2014.

One of the most successful BBC Dragons' Den rejects ever, Rob Law asked for a $127,000 (£100k) investment in Trunki, his ride-on children's suitcase business back in 2006. Humiliated when Dragon Theo Paphitis broke a strap on one of the cases, Law left empty-handed.

Much to the Dragons' regret, Law had sold two million Trunkis by 2014 and has made millions out of the ride-on cases, which are now a must for families with young children worldwide.

Melissa Butler's vegan lipsticks were mocked and compared to clown make-up by the investors on the US Shark Tank.

Yet following her disastrous appearance on season six of the show in 2015, Butler has seen her business flourish. Lip Bar revenues have more than doubled and Butler has secured stockist contracts with Target stores in Detroit, New York and Los Angeles.

Down Under, Melbourne natives Steven Johnson and Christian Schaefer had no joy when they pitched their airport car-share idea to the venture capitalists on Channel Ten's Shark Tank show in 2015, failing to secure a much-needed investment of $227,000 (£179k).

The show's investors may have passed on the buddies' Carhood concept, but the idea caught the attention of Ford Australia, which signed a deal with the duo last year. The company is now worth at least $4 million (£3.2m) and Carhood has become Australia's leading car-sharing service.

Ridiculed as a “hair-brained” idea by investors on the BBC's Dragons' Den show back in 2007, Shaun Pulfrey has since made his genius Tangle Teezer a virtual household name.

Popular among celebrities including Victoria Beckham and Cara Delevingne, the product is now an essential piece of kit for people with long, unmanageable locks. Pulfrey's company was valued at a cool $253 million (£200m) last year.

Shawn Davis' gourmet seafood burger concept was given the big thumbs-down by investors on season two of the US Shark Tank show, and Davis left with nothing.

More fool them. The seafood fan has overseen a massive sales increase since he appeared on the show in 2011. The one company Shark Mark Cuban wished he'd invested in, Chef Big Shake is now turning over revenues exceeding $1 million (£790k) a year.

Thankfully, Natalie Ellis wasn't discouraged when her non-spill water bowl for pets was rejected by investors on the BBC's Dragons' Den show in 2008 and her plans to expand to the US were derided.

Making her first million pounds by 2010, the savvy entrepreneur has seen sales of her bowl soar worldwide since her appearance on the show. Former US President Barack Obama has even snapped up a Road Refresher for his dog Bo.

Mona Weiss and Scott Shields failed to secure a $150,000 (£118k) investment in exchange for 15% equity when they pitched their environmentally-friendly non-toxic detergent business to the Shark Tank investors in season four of the US show.

Not that it made any difference to the entrepreneurs' success. The media exposure they received from appearing on the show has fueled skyrocketing sales and the enterprise is now worth in excess of $1 million (£790k).

A former taxi driver, Rachel Lowe used her cabbie know-how to create the taxi-themed Destination London boardgame and took her idea to the BBC's Dragons' Den in 2004, where it was savaged by the investors.

London toy megastore Hamleys was a lot more positive and began stocking the game later that year. It remains one of the store's bestsellers. Now a multi-millionaire, Lowe has since expanded to other titles, created a fashion brand and picked up a British royal honor along the way.

Screenwriter-turned entrepreneur Michael Elliott hit a brick wall when he appeared on the US Shark Tank in 2014, unable to sweet-talk the investors into investing in his male nail bar and beauty salon franchise.

Shark Kevin O'Leary advised Elliott his franchise business would never work. But since the show aired, the male beauty entrepreneur has raised the required $200,000 (£158k) investment cash from angel investors, and sold an impressive 183 franchise licenses in eight US states.

Daring to enter the Dragons' lair in 2014, Nikki Frith and business partner Lindsey Oldroyd left with nothing for their quirky marmalade business after a fraught appearance on the BBC show.

Failing to bag the $63,000 (£50k) investment they were after didn't spell the end of the duo's business dream. By a long shot. In fact, Granny Cool Marmalade has amassed a whopping 150 stockists in the UK alone and business is booming.

Dan Cluderay and business partner Andy Needham appeared on the BBC's Dragons' Den show in 2014 seeking a $191,000 (£150k) investment in their business, which sells out of date but perfectly edible food to cost-conscious shoppers.

The Dragons would have got 10% equity in the firm if they'd stumped up the cash, which must hurt given how well Approved Food has been doing of late. Securing investment elsewhere, Cluderay and Needham have built up a formidable business and Approved Food now turns over $5.1 million (£4m) a year.

When sustainable energy entrepreneur Michael Zimmerman pitched his Group IV Solar business to the investors on the Canadian version of Dragons' Den in 2014, he got a real grilling. The Dragons rubbished Zimmerman's business plan and he left the CBC show with zero investment.

Fast-forward to 2017 and Zimmerman's solar energy enterprise is booming. The clean energy trailblazer has managed to set up a solar farm that produces enough energy to power 100,000 homes, netting him millions of dollars.

'Healthy' ice cream is all the rage right now and brothers Harry and Charlie Thullier have tapped into the trend with their Oppo low-calorie ice cream. The siblings took their idea to the investors on the UK's Dragons' Den show last year, but left without the $76,000 (£60k) they were seeking.

Not to be deterred, the brothers opted to crowdfund their idea. By the end of 2016, Oppo had garnered hundreds of investors, including Richard Branson and tennis star Andy Murray. A major success, the virtuous ice cream is now stocked in 1,300 stores across the UK.

Dismissed as “poppycock” by investor Duncan Bannatyne, John Richardson's face cream, a natural alternative to Botox, was wholeheartedly rejected by the panel on the BBC's Dragons' Den show in 2011.

Getting his own back and then some, Richardson pressed on with his business and landed a contract with London department store Selfridges later that year. The cream is now sold in 15 countries and has made its creator millions of pounds.

Greg Bay's request for a $378,000 (£197k) investment in exchange for just 15% of his sports compression shorts business went down like a lead balloon back in season two (2007) of the Canadian version of Dragons' Den.

Not that it mattered in the long run. Not long after the show aired, Bay clinched a deal with sportswear giant Under Armour, which now manufactures the shorts and markets them to NBA, NHL and NBA athletes.