Irish nationality as a competitive advantage: "Ireland is going through a popularity phase at the moment, " Twohill says. "They can talk about Cool Britannia, but it's more Cool Hibernia now." That said, Twohill notes that "there are so many nationalities in Google, and if you're considered good, you're good no matter where you come from".

Reasons to stay in London: "I'm in the UK because my team is here. It's our largest market in Europe and one of our biggest in the world. London is a centre of advertising resources and I need to be around them." But the London-Dublin route is "like a shuttle service". She returns to Ireland once a month.

RORY GODSON PARTNER AND CO-FOUNDER, POWERSCOURT The lowdown: Godson's ascent from grubby journalism to habitué of UK plc boardrooms has been astonishing.

The Sunday Tribune hired the young Godson as a sports subeditor in late 1980s, and promoted him to deputy editor.

Stints at other Irish newspapers and a job as Irish editor of the Sunday Times followed. Poacher became gamekeeper when the world of PR beckoned. Godson joined Goldman Sachs as European director of corporate communications but, never one to let the grass grow under his feet, quit after a year to set up Powerscourt, advising such clients as Aer Lingus, Eircom and BP on their media relations.

Networking: Godson gets together with fellow London-Irish business people through the Irish charities he helps.

He describes such networking as "subconscious" but acknowledges that his agency does gain a lot of work from Irish clients. "Because we are culturally attuned to Irish sensibilities, working out what Irish clients want is easier for us. You get to the same wavelength more quickly."

Reasons to stay in London: The key factor keeping Godson in London is business opportunity. "Our Irish clients want us to operate here and we have a rapidly developing international business too. You need to be on the ground, going to events and parties and having coffee with editors to tell your clients' stories." Godson doesn't rule out moving back. "Happily we have a house in Dublin so it is relatively easy to move back and forth."

KEVIN BROWN HEAD OF ENGAGEMENT PLANNING, BARTLE BOGLE HEGARTY The lowdown: Brown is one of London adland's most influential media experts. It's all a far cry from when he went to the UK aged 22 in the 1980s after completing a marketing course at the College of Commerce in Rathmines. Having been introduced to media planning and buying at Nestlé, Brown then experienced ad agency life at BMP and Bartle Bogle Hegarty. He honed his specialist media skills at Starcom Motive, leaving in 2000 to set up Soul, an agency he sold in 2005 to an Asian network. Last year Brown was headline news in Campaign, the UK ad magazine, when he rejoined BBH to establish a new planning division.

Irish nationality as a competitive advantage: "It's no disadvantage. The Irish are pretty open, friendly and good communicators, which is important in a communications business."

Reasons to stay in London: Brown's wife is English and they have two children. "Once your children start building a world in this environment, it's harder to up sticks and leave, " Brown says. The other big incentive to stay is the global horizons offered by London and by BBH. "There are centres of excellence in the ad industry and London is one of them."

PAUL WALSH CEO, SEGALA The lowdown: One of AOL's first employees in Europe, Walsh is a selftaught internet technology whiz who combines running his web accessibility and mobile testing agency Segala with chairing the UK internet trade association BIMA. He sits on the World Wide Web Consortium (W3C) advisory committee and is a key member of the Mobile Web Initiative (MWI) steering council. Before founding Segala in 2001, Walsh consulted for mobile phone giants such as Vodafone and Orange. His career beginnings were not so lofty:

Walsh's first job involved filing and lugging computers around for a Dublinbased bank.

Irish nationality as a competitive advantage: "I've been at international events where I've been told: "you Irish can get away with anything with that accent". He admits to being "quite proud" that an Irish person is heading the UK internet trade body.

Networking: Walsh is an assiduous networker amongst internet technology types, regardless of nationality.

Based with his family in Guildford, Surrey, Walsh divides his time between Segala's offices in Dublin and the UK, with travel around the world to speak at conferences and to visit clients.

DEE FORBES SENIOR VICE PRESIDENT AND GENERAL MANAGER, TURNER BROADCASTING SYSTEMS UK AND IRELAND The lowdown: UK London's advertising business was the making of Dee Forbes, senior vice president and general manager of Turner Broadcasting Systems UK and Ireland. Arriving in the UK capital 16 years ago armed with an arts degree from UCD, the Cork woman began her career as a lowly sales executive at ad agency Young and Rubicam Europe. Promotion has led to her current position at Turner, where she is responsible for all the channel's commercial activities, including marketing and PR.

Irish nationality as a competitive advantage: Forbes doesn't believe that nationality is an issue in London's business world, and apart from occasionally speaking more slowly, has never felt she had to compromise her Irishness. Forbes notes one undeniable positive. "I came to London 16 years ago as a green graduate and luckily the Irish have a strong work ethnic so we can make it here."

Reasons to stay in London: "It would be difficult to get something as senior as this at home, " Forbes admits. "But I return a lot to Cork where I have a house and so have the best of both worlds."