London-based British mattress retailer Simba has closed a £5m investment round from Spark Ventures and The Garage Soho, alongside a group of angel investors.

The new investment will be used to grow sales internationally, now the company's approach has been  successfully tested in the UK, France, Germany and the Netherlands. The money will also be used to strengthen the company's market presence in the UK.

This is the second round of funding for the business, which was founded in August 2015 by serial startup investor James Cox, the founder of Tribesports.com Steve Reid, and mattress veterans the McClements family.

Simba – a one-type-fits-all, next-day delivery, bed-in-a-box solution – initially secured backing from a series of UK investors including Richard Reed, the co-founder of Innocent Drinks.

Simba’s investors now include a growing list of business leaders including: Tom Teichman (made.com, lastminute.com, notonthehighstreet.com); Nigel Wray (formerly Domino’s Pizza, Saracens, Prestbury Investment Holdings, Franchise Brands Plc); Richard Reed, Adam Balon and Jon Wright (Innocent Drinks); and the Jatania Family (formerly cosmetics giant Lornamead – Vosene, Yardley).

According to Simba, its is now the market leader in the bed-in-a-box sector, 20% ahead of rivals Eve and US brand Casper. In just seven months the ecommerce start-up has sold 15,000 mattresses – around £10m in sales. An exclusive deal with John Lewis has bolstered this performance.

CEO and co-founder of Simba Sleep, James Cox, says: “This year has been incredible. Whilst Casper may have rushed to launch in the US with its memory foam-based bed-in-a-box offering, we knew from our research that we could create a premium offering which offers more comfort and support for over 95% of the British public.

"We were the first to develop the hybrid dual spring and memory foam mattress – which was then rigorously tested with the Sleep to Live Institute who have compiled data taken from 10 million people. We know the Simba mattress is the best on the market, and our low returns rate speaks for itself in comparison to our competitors.”

Simba offers next-day delivery, and a 100-night return service.

“Casper was only founded in the US in 2014," continues James, "yet has achieved staggering results, turning over circa. $100m-plus last year alone. We are now leaders in the UK and will have launched across Europe, Asia and North America by the end of the year. We love the challenge and embrace the competition.”