Dan Wagner has never backed down from a business fight. Now the serial entrepreneur is taking on Jack Dorsey, co-founder of Twitter and darling of Silicon Valley.
Powa Technologies, one of the smooth-talking Londoner's companies, has developed a mobile payments system similar to Mr Dorsey's Square, the dongle that turns mobile devices into payment card readers. He even used the same stock shot as Square to promote it, which earnt him a "cease and desist" letter from the US company's lawyers in July.
"It was the best publicity we could have had," he says cheerfully and unapologetically over lunch in a Manchester restaurant. "We got coverage and lots of business inquiries on our website. We are already in discussion with US banks. We are going to take the fight to them."
Mr Wagner, 49, says he has "never been involved in something as exciting as this" in an eventful business career spanning almost 30 years. Banks, telecoms and software companies are all pushing consumers to use mobile phones as a payment tool. But Mr Wagner is convinced that Visa and MasterCard will maintain their grip on the infrastructure. Rather than create a new system, as Square has done, he wants to build mobile payment services in collaboration with the banks.
Powa's newest product, mPowa, will improve current payment systems, he says. Far smaller than the bulky payment terminals currently used in restaurants, for instance, its card chip reader connects via Bluetooth to the merchant's mobile and sends a receipt by text message or email to the cardholder. It levies a 0.25 per cent fee per transaction on top of what the card services provider charges, usually about 2.5 per cent.
Unlike Square, which Mr Wagner sees as targeted mainly at small retailers who do not currently take card payments, he believes mPowa will appeal to big companies with a door-to-door salesforce, or those who want to claim payment on delivery. "Over 70 per cent of Square customers transact less than 20 transactions per year or less. They have a mud hut. I have a skyscraper," he says.
MPowa has one big advantage over Square: it uses the chip-and-pin technology that is widely used in Europe, Africa and Asia, whereas US-based Square can only handle the magnetic stripe. South Africa's First National Bank, the retail and corporate division of First Rand, one of the country's big four banks, in September became the first company to adopt the mPowa card reader and software, for which it will pay an annual fee.
Banks and others can also adapt it and label it as their own. "We are a 'white-label solution'. Square is a closed system," Mr Wagner says.
In a sharp pinstripe suit and with his full head of greying hair swept back, Mr Wagner seems more sombre than when he rose to prominence in the 1980s. Back then he was as famous for his Donald Duck waistcoat as for his achievements as one of a new breed of entrepreneur unleashed by deregulation.
After leaving school at 16, he worked as a shop assistant for Julian Richer, then an aspiring entrepreneur whose hi-fi store Richer Sounds is now worth an estimated £50m. "Seeing Julian do it at 17 made me think I could start a business. You need role models," he says.
He left to work with as an account executive at WCRS, a leading advertising agency, where he conceived the idea of creating a digital record of information about business sectors gathered from newspapers and other publications to form a resource for marketing professionals.
He gave up his job and used a scheme aimed at helping the unemployed to found Maid (Marketing Analysis and Information Database). "When I told my mother she burst into tears," he says. "When I got a job in advertising she thought I had made it. My dad was encouraging though.
"Back then there was no structure to invest in start-up businesses. This was 10 years ahead of the internet."
Maid captured 26 per cent of a burgeoning market. It floated in 1994 but the shares dived, and the company, renamed Dialog, was quickly dubbed "dial a dog" by some City investors. In 2000, it was sold it for $330m to Thomson, the newspaper group.
A year later, he founded Venda, which runs ecommerce websites for retailers such as Tesco, Superdrug, JVC, Urban Outfitters, CondÃ© Nast and Jimmy Choo. It was based on technology bought from Boo.com, an early online clothes retailer that crashed spectacularly during the dotcom bubble.
Bright Station, the holding company for Mr Wagner's various businesses, has an annual turnover of about $50m, he says, and employs 450. It includes Powa, an ecommerce and web publishing platform for small businesses, Locayta, which allows retail websites to promote products through searches, Aigua Media Group, featuring fashion and female-focused blogs, and the social shopping platform Osoyou.com, which claims to have more than 1.4m unique visitors a month.
For an entrepreneur who has started and sold several businesses, continuity seems surprisingly important. He has lived in the same north London house for 20 years, and attends Arsenal football games with childhood friends.
In fact, Mr Wagner remains a surprising loner in the networked world of entrepreneurs. He admits, for example, to leaving a Google party attended by Rupert Murdoch early to catch an episode of 24 on television.
He credits his modest upbringing for his tastes. Although his father was the UK managing director of BMW, "the salaries weren't like they are now", he says. "I'm happy. We had our holidays in Birchington on the southeast coast of England. I can take my daughters to Italy and Spain."
Mr Wagner has spent £8m of his own money developing the mPowa product. Square closed a $200m fundraising in September and takes $8bn of payments annually.
Mr Wagner, however, is in no doubt that Powa Technologies will one day catch it up, and says that the first bank deal gave others a "jolt". But he envies Silicon Valley's ability to raise money. "It is a terrible shame we do not have a venture capital industry that supports initiatives like this. We are the financial capital of the world."
He has, however, no intention of becoming an angel investor himself and helping others get started. "I would never invest in things other people do. I have enough ideas myself and using my money means I have no need to convince other people."