Ajith Jayawickrema is a two-time winner at building fast-growing, casual dining businesses that thrive on a party atmosphere. He arrived in the UK from Sri Lanka aged 15, without a word of English. At 16 he worked at McDonald’s.

He read economics at Birmingham University, adding an MBA from Sheffield University (“for depth and breadth”) and then worked in fashion wholesale and at a retail consultancy. His main ambition, though, was to start a business.

A fly-drive holiday to California in the early 1990s turned Jayawickrema on to Mexican food. He returned to the UK intent on starting a Latin American-themed restaurant and went in search of a loan.

“I couldn’t get a penny out of Mr Blood, my bank manager,” he says. Until, that is, he asked for £10,000 to buy a car.

Jayawickrema and his business partner and school friend Eren Ali opened two Las Iguanas restaurants within a year, the first in Bristol, where Jayawickrema is based. By the time he had opened a third, Jayawickrema felt able to tell his conservative parents what he was up to.

After three venture capital deals and dozens of restaurant openings, Jayawickrema exited the group in 2009 following a life-changing bout of dengue fever. He relinquished his holdings in Las Iguanas when the 41-site chain was sold to Casual Dining Group for £85m in 2015.

It was Leona Lewis’ X Factor win in 2006 that inspired his next venture, the Caribbean-themed Turtle Bay. “As an immigrant, I thought it was incredible: millions of people had voted for her – her race, her colour, her ethnic background didn’t matter,” he explains. Jayawickrema immersed himself in studying Caribbean food, cocktails and reggae.

He had already worked with Pitcher & Piano founder Crispin Tweddell when the latter’s private equity firm Piper invested in Las Iguanas. Tweddell invested in Turtle Bay, which opened its first outlet in Milton Keynes in 2010. Now, the business has more than 50 sites and a turnover of £90m.

Citing Piper’s 7/17/70 theory, Jayawickrema also believes there are three critical stages of development for a business: when turnover hits £7m, £17m and £70m.

“When you’re at nought to £7m, the costs are low and you work the assets hard,” says Jayawickrema. “In the process, you realise what you need to change and refine. It’s like test marketing.”

By the second stage, it’s more of a big deal, he believes. “It’s time for a new team of executives. You need a regional director,” he adds. Recruiting the right people that the business needs becomes even more important. “You have to hire a team that’s better than you,” he says.

“At £70m, it all changes,” Jayawickrema says of the third stage, when non-executive directors have to be brought in. “You need more of a focus on the process. It’s a real challenge to founders.” He describes these three phases as entrepreneurial, semi-corporate and, finally, corporate.

Even after his experience in property, finance and kitchen design, there are still plenty of hurdles to overcome on the path to fast growth. “In Sheffield, we had to spend a third of the budget on a ventilation system,” he recalls. “The air coming out was cleaner than it was going in.”

In the past, Jayawickrema has tended to step back after hitting between 40 and 50 sites. He is now Turtle Bay’s non-executive deputy chair, with the ownership shared between him, Tweddell and Piper. You have to wonder whether he will be tempted to chase a hat-trick of successes.

Read about more inspirational businesses in our Growth Stories series.