The hit BBC show Dragon Den has seen some of the most successful hit products hit stores in recent years. 

But the Dragons haven't always spotted a good deal, with many of the hundreds of products featured on the show seeing success without the aid of the Dragons. 

From the beer company Brewdog to the surprise hit of the small hairbrush the Tangle Teezer.

We've looked at all the products featured on the show over its 18 seasons and found the biggest missed opportunities. 

Trunki

The Trunki is a ride-on hand luggage suitcase for children that although didn't receive investment has become a multi-million business. 

Created by Rob Law the children's trunk was turned down after Theo Paphitis broke a strap of the suitcase leading to Dragons questioning the quality. 

However, Paphitis has since regretted the remarks as Trunki is the most successful product never to be invested by the Dragons, making revenue of £8.13 million. 

The suitcases can be brought from Argos, Amazon, Boots, and Trunki. 

Tangle Teezer

Back in 2007, Shaun Pulfrey pitched the idea of a new hairbrush that would brush tangled hair into a smooth glide. 

But when showing the Dragon's his new product it did not go to plan, seeing his appeal for £80,000 fall down the drain. 

But was later praised by Victoria Beckham and named Entrepreneur of the Year in 2016. 

The brush can be brought from Amazon, Superdrug, and Boots.

Hungry House

Online takeaway service fell through on Dragons Den when Shane Lake and Tony Charles turned down Duncan Bannatyne's £100,000 offer. 

Without the help of the Scot's, the business merged with JustEat and made a nice sum of £240 million. 

Destination London!

Back in series one taxi driver Rachel Lowe pitched the idea of a new board game inspired by London. 

But when Dragon Rachel Elnaigh said Lowe wasn't prepared enough, her sought of £75,000 was gone. 

However, in 2008 Lowe's game had outsold every other game in Regents Street Hamley's store.

She soon signed a deal with Disney to make a spinoff of Destination Animation and was even awarded an MBE.

You can buy the game from Amazon.

Cup-a-Wine

James Nash pitched his idea back in 2009, with the creation of a sealed plastic cup that contains one serving of wine. 

The dragons didn't see the potential and missed out on the now huge product that is a staple for commuters and scenic picnic spots. 

Brewdog

Now a household name, Brewdog started as a venture by James Watt and Martin Dickie. 

The pair asked for an investment of £100,000 in return for 20% but the idea didn't appeal to the Dragons. 

Now that small idea is worth £360 million and has restaurants and bars across the county.