Two years ago Mark Jankovich received a multi-million pound job offer from Goldman Sachs. He turned it down and went into toilet cleaning instead.

It’s not a decision most City bankers would make but the former head of family wealth management at Coutts & Co has no regrets about turning his back on his former life. “I called my wife and said, ‘I just can’t do this’. I was hating it. I didn’t believe in it. I wanted to find something more useful to do,” said Jankovich, 40.

First, he set up a private-equity firm to invest in his native Zimbabwe. He spent a year raising money but returned it to investors after Robert Mugabe won the presidential election last June. He then began casting around for environmental business ideas and found Delphis Eco, which makes biodegradable cleaning chemicals, through a Google search. The company had been started a few years earlier in Liverpool by two business partners. Its range, for everything from toilet cleaners and hand sanitisers to industrial disinfectants, uses plant-based ingredients, such as coconut oil, that break down naturally.

The range was the first in Britain to receive the EU’s Eco-label accreditation, given only to products made from sustainable sources that are proven to be as effective as conventional rivals.

When Jankovich learnt of Delphis Eco, however, it was on the brink of collapse. “It was in an absolute tailspin. A lot of time and money had been spent on research and development. They had hocked a lot to keep the dream alive. It was scary to step into a business like that,” he said.

He was convinced that the opportunity was good enough to take a risk. Businesses and organisations are under pressure to go green and switching from hazardous chemicals to ones that are environmentally friendly is an easy way to make a significant difference, especially for big concerns such as supermarkets or rail firms that have many shops, offices and washrooms that need constant cleaning.

Jankovich invested £500,000 to buy out the founders a year ago. Since then he has been spreading the word about environmentally-friendly cleaning. Bunzl uses Delphis products in its green cleaning range. J Sainsbury, Tesco and Marks & Spencer, local councils and the Metropolitan Police have also expressed an interest.

Delphis Eco is still small. It has fewer than 10 staff and relies on two contract plants to make the chemicals. Jankovich is hoping to raise £2m of venture capital to compete with Johnson Diversey and Ecolab, which dominate the market.

“Much of this is about opening the eyes of consumers,” he said. “They simply don’t know or don’t think about the fact that they can get ‘green’ chemicals.”

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