At first sight, Bob Gilbert and Lesley Cowley are an unlikely management team. Mr Gilbert is a relaxed, outgoing and affable company law specialist who sits on the board of several public companies and has a lifelong passion for motor racing. Ms Cowley on the other hand is an unassuming yet determined behind-the-scenes player, focused on precise detail and day-to-day operation.

Together, as chairman and chief executive respectively, they run Nominet, the not-for-profit company that is the UK's answer to the giants of the internet business.

What Nominet does is largely invisible to companies and consumers - and for good reason. It administers and runs the UK internet registry, meaning all the domain names in the world that end with ".uk".

So whenever a .uk address - either a ".co.uk" or any of the other 13 possible endings including .me.uk and plc.uk - is registered, transferred, moved or argued over, it is Nominet's job to make sure the process runs as smoothly as possible. With more than 4.5 million .uk domain names, and new domains entering the system at a rate of 150 every hour of every day, that is no mean task.

Since its inception ten years ago, Nominet has remained in the background - you could buy a .uk domain from the company but it would far rather you bought it from one of its 3,000 members - but Cowley and Gilbert are looking to change all that.

Next month, Nominet will ask members to approve changes to the company's Memorandum and Articles of Association that will see it free to pitch for business outside the .uk registry. If approved, the changes will mark the end of the first phase of Ms Cowley's radical reorganisation of the company.

Joining as operations director in April 1999, Ms Cowley worked her way to deputy managing director in 2001 and then managing director in March 2002. But her desire to use Nominet's good name and expertise to become a force in the internet industry was stymied by the company's own rules and the fact that the company's founder and internet pioneers, Dr Willie Black, remained as chairman.

When Dr Black resigned in September 2004, Ms Cowley brought in Bob Gilbert - a specialist in company law with wide business experience but with little or no knowledge of the internet industry. Mr Gilbert arrived in May 2005.

The decision to go for someone without internet experience was a conscious one, Ms Cowley admits: "We chose Bob because he did not have industry experience so he would have a fresh perspective and view of us."

While Mr Gilbert has spent most of his time reviewing Nominet's governance, culminating in the changes that will be put forward next month, Ms Cowley has set about transforming Nominet from within.

She changed her job from the UK-style managing director to the more modern chief executive in January 2005. Nominet hired more staff, redesigned its systems and started to carve out a new furrow in the domain name market.

Anyone who registers a .uk domain now receives not only a certificate but also a personalised pin-code in the post. No other internet domain provides the same sense of ownership and the idea, Ms Cowley explains, is to make the domain name system easier for people to understand. "People just want these systems to work, and we want to make sure a name is safe and secure."

At the same time, Nominet's legal team has aggressively tackled important issues at the heart of the internet, including fraud and theft of data, that most registry owners prefer to sidestep. As a result it has won a series of important legal judgements both in the UK and abroad and started to build a foundation of internet law that was rewarded with a Legal Week award earlier this year.

The staff has expanded to 130, the company is moving to a new, bigger building in Oxford's Science Park next year and Mr Gilbert states that one of the things he is most proud of is the company's appearance in The Sunday Times'Best Small Companies to Work For. While this expansion has gone on, Nominet has continued to charge its members the same price for registering .uk domains - £5 - while increasing turnover to £12 million and building a potential warchest of a few million pounds.

The company has also raised its public profile, attending public meetings, and advising companies and governments about the latest technologies and their risks. Only this month, it spoke at a United Nations meeting on the future of the internet.

But just as Nominet finds a firm footing, it faces probably its greatest challenge. The rise of internet search engines has meant that the domain name system itself is becoming less important as people use, say, Google rather than type a specific name into their Web browser. At the same time, a new wave of technologies are starting to use the internet in radically different ways.

The rapid rise of free telephone calls over the internet, and with more consumer devices connecting to the Net each year, Nominet is keen to use its expertise to grab the registry equivalents of the future. "We are at a crossroads now," Mr Gilbert says, "we could stagnate and go downhill. Or we could go uphill in very exciting ways."

Ms Cowley is keen that Nominet bids for an upcoming contract in the UK for what is called ENUM. Put simply, ENUM links traditional telephone numbers to internet addresses, a sort of e-directory service that provides what many people believe will be the vital link between old and new ways of communicating. That contract could be just the beginning of Nominet challenging the big beasts of the internet on a range of contracts across the globe. Except, under its current governing principles, Nominet is not allowed to bid for ENUM.

Mr Gilbert says he wants Nominet to become "that respected voice on the internet". Ms Cowley says the company has "grown up a lot" and its successes outnumber its errors. "We have a lot to celebrate on our tenth birthday," she said, "and I want to make sure we have as much to celebrate in the next ten years."

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