WHEN the internet revolution came, the world thundered. A new technology, a new business and a new way of living had appeared that was tearing up the rule book. It eventually saw hundreds of hopefuls going to the wall, yet out of the wreckage emerged a band of people who would lay down the foundations of a rock-solid industry paving the way through the 21st century.

Proving the value of self-belief and that you can build an international market-leading firm from Scotland, Steve and Heather Leach are among the lucky ones.

A well-oiled husband and wife team, they risked everything they owned to launch a three-person company at the dawn of the internet age. Last year saw their company, Bigmouthmedia, complete a Carlyle Group-backed £60 million reverse takeover of German digital marketing giant Global Media, a deal that earned the Leaches a healthy personal fortune, a hat-trick of major entrepreneurial awards and a reputation as two of the smartest operators on the scene today.

"It's been a wild ride, and sometimes it's pretty hard to believe, but we're still so busy that it's not something either of us really has time to dwell upon. When we launched the business in 1996, I always thought it was possible we could build it into a major international company, but if truth be told I never thought for a moment that it was very likely," says Steve.

I first met Steve Leach over a decade ago, when I was a technology reporter and he had just launched a web services company called Vertigo Web Design from the basement of a former pet shop in the Ferry Road area of Edinburgh, one of the city's least fashionable quarters. Since then he has built an international company, earned a multi-million pound personal fortune and moved into Scotland's most expensive private home ... but I still have a full head of hair.

They launched - at Heather's suggestion - one of the thousands of one-stop-shop web design, hosting and services operations that sprang up in the early years of the web phenomenon. As a public relations professional, Heather took care of the company's marketing and PR while Steve, a former firefighter and commercial pilot, concentrated on the business's client base.

Having begged and borrowed to finance the start-up business, the pressure on both their commercial and domestic lives was enormous but they won through, they believe, due to the application of a set of family regulations.

"Running a business together did put extra strain on the relationship, but we have rules. At dinner time, shop talk is banned from the moment the first course is over and all work-related topics are strictly off-limits the instant our holiday flight lands, though Steve breaks that one all the time," says Heather.

As the century turned, the Leaches recognised how crowded the general web services marketplace was getting and decided to concentrate instead on their core strengths in managing online advertising campaigns, search engine optimisation (SEO) and brand protection. For the uninitiated, SEO employs a host of tricks of the trade to ensure that a company features as highly as possible on search lists on Google and other search engines. Brand protection is about trawling the web to ensure that nobody is misusing a company's brand for their own purposes and working with lawyers and other agencies to have any such activities stopped.

Considered a maverick move at the time, focusing on these areas proved to be smart, and while internet businesses began to go bust by the dozen, the rebranded Bigmouthmedia was emerging as a leader in a sector they are credited with helping to create.

Today the operation provides digital marketing services to over 350 of the world's biggest brands including British Airways, Tesco, Starbucks, Adidas and BP. Signing all customers on month-to-month rolling contracts from which they may withdraw at any point, Steve Leach believes that the company's success is due to a policy of providing hard and fast numbers to back up the claims his company makes.

"Marketing is a very soft business with few solid measures, but we're a digital marketing company and there's a big difference. In the online world everything's hard, there are auditable statistics, robust reporting software and no excuses for a client not knowing exactly what they're getting for their money," he says.

"We've avoided going into areas where the results are too nebulous At the end of the day their return on investment is either positive or it's not - that's all that counts."

The numbers don't lie, and Leach's obsession with delivering measurable results has clearly paid off. Swelled by the acquisition of Global Media and now employing more than 200 staff in 13 offices across 10 countries, Bigmouthmedia's global annual turnover currently stands at £100 million, making it Europe's biggest digital marketing agency.

When the news broke of the £60m Global Media deal at the very tail end of 2006, most expected Bigmouthmedia to be swallowed up by the larger German company. Carlyle Group, which brokered the deal, saw the two as a perfect fit, but decided that the Scottish brand was the strongest, and that the entire operation was to be rebranded accordingly.

Although Global Media founder Thomas Gerteis and the Leaches both retained large personal investments in the company, in March 2007 Gerties stepped down to spend more time with his family, and Steve was named the new organisation's global chief executive.

The Leaches refuse to rest on their laurels. Now focusing on the company's further expansion, they concede that having devoted so much of themselves to raising their commercial baby, letting go of some aspects of the operation has proved a challenge in itself.

"I do find myself sticking my nose in and the regional managing directors don't always like that. It sounds easy to say I'll get someone else to do that', but in reality it's incredibly difficult to find somebody I can trust to look after the company I built and then just leave them to it," says Steve.

"I'm learning to look at things from a group level these days. I look at the figures every month and if someone's missing them or not making their targets, I'll be right in there looking for an explanation, but the people we have in place are more than capable."

With the integration of the merged companies close to completion, the Leaches intend to devote 2008 to Bigmouthmedia's continued geographic expansion, with a blend of buyouts and fast-tracked local launches. Having recently completed the move to new premises in New York, the business will also concentrate on expanding its US client base. There is also speculation - to which the Leaches offer no comment - that there might be a flotation next year.

It doesn't sound like it, but the couple will have some time for leisure too. Their private life is something they prefer to keep to themselves, however, and while Leach may call himself a bigmouth, he is curiously reluctant to talk about his involvement in several charitable social networks.

"It's something we do for ourselves rather than for business," he explains. "I don't want to be one of those people who makes profit out of charity work. If the situation demands greater involvement I'll look at it again, but for now it's very much a private commitment."

Looking on with the patient expression worn by all experienced wives, Heather smiles at this point, believing that it sums up what her life and business partner is all about.

"Steve is a bigmouth," she says, "but his heart's in the right place.".