Transcript of Video:
It's not obvious but this is the legal and tax base of one of the world' largest oil rig firms. Rowan Companies is worth $4 billion and employs 3,500 staff. But hardly any of them work in the UK - the London office was set up to help the company avoid a higher U.S. tax rate. It's certainly done that - last year Rowan paid 3.3% instead of 34% in 2008. Reuters' Tom Bergin says it's not the first U.S. firm to move here for that reason. SOUNDBITE: Reuters journalist, Tom Bergin, saying: "A U.S. company can, even just nominally, establish itself here in London and channel profits into tax havens, take them back here to the UK, pay the money to shareholders and not pay taxes in the way that they could not do if they remain based in the U.S. or indeed if they were based in any other major trading partner like Germany." Rowan and six other major companies, including U.S. insurer Aon and communications conglomerate Liberty Global, have re-located their headquarters to the UK in the past year. Drugs giant Pfizer and Omnicom also tried to - but failed takeovers scuppered their plans. Several more multinationals are reportedly waiting in the wings. London is no Cayman Island even though the weather - for once - might be reminiscent of a Caribbean tax haven. But two years ago it did change the law, effectively meaning the government no longer taxes profits made abroad - unlike in the U.S. The UK's Finance Minister George Osborne is delighted with the interest from multinationals. He says the foreign businesses help create jobs and boost government revenue. But tax lawyer Kevin Phillips isn't convinced. SOUNDBITE: Baker Tilly International Tax Partner, Kevin Phillips, saying (English): "If you have got senior executives based in the UK, then it's an act of faith that around them, you're going to need to assemble support and they're going to be highly paid and they're going to spend that money and there's also this faith that there will be this snowball effect that once a major company has its headquarters in the UK, it will see the benefits of the UK as a place to do business." The UK denies it is a tax haven - insisting it has a reasonable 20% corporate tax rate. But Britain could eventually be forced to legislate. SOUNDBITE: Reuters journalist, Tom Bergin, saying (English): "If it continues to be the case that companies continue to significantly cut their tax bills, overseas and potentially even their UK tax bills, through these measures, without creating many jobs, the pressure could grow on the government to rethink these measures." President Obama has promised to try and stem the flow of the so-called "inversions." But government red tape means new laws won't happen any time soon. And that means Pfizer probably won't be the last to look across the Atlantic for money-saving opportunities.