There has been speculation, however, that New York may be problematic, because US Securities and Exchange Commission rules would almost certainly require Aramco to divulge information about Saudi oil reserves that the kingdom regards as a matter of national security.London’s main problem would be the weak value of sterling, though the value of the pound could shift by 2019 once the Brexit deal is finalised.The Aramco IPO is part of a larger Saudi strategic plan called Vision2030, aimed at diversifying the country’s economy and reducing its economic dependence on oil and gas.The proceeds of the IPO will be used by the Saudi government’s Public Investment Fund and Mrs May hopes a chunk of that money will be invested in post-Brexit Britain. Theresa May attends a meeting at the Saudi Stock ExchangeCredit:Simon Dawson/Bloomberg The Prime Minister will end her visit to Saudi Arabia on Wednesday by having a working lunch with King Salman.Mrs May hopes Britain will gain from the Aramco Initial Public Offering (IPO) twice over – by persuading the Saudis to hold it in London, and by encouraging them to invest the proceeds of the share sale in Britain. Theresa May is in talks with Saudi Arabia’s state-owned oil company to use the London Stock Exchange for the biggest share flotation in history.Saudi Aramco is expected to be valued at £1.6 trillion when it sells five per cent of its shares on the open market.The flotation will be hugely lucrative to the city that hosts it, when shares worth millions of pounds will change hands.On Tuesday evening, Mrs May held a meeting with the Aramco chairman Khalid Al-Falih, who is also Saudi Arabia’s energy minister.Significantly, she was accompanied by Sir Xavier Rolet, chief executive of the London Stock Exchange, the only British businessman in the room during any of the meetings Mrs May has held in the kingdom. Downing Street said the Prime Minister had “set out the advantages of listing in London”, such as the “depth of expertise” in financial services, accountancy and the law.Sir Xavier also attended a second meeting this morning with executives from Saudi Arabia’s Public Investment Fund – the world’s largest sovereign wealth fund – which will be the beneficiary of the Aramco flotation, which is expected to happen in 2019. New York, Hong Kong, Tokyo, Singapore and Toronto are all rivals for the IPO but New York and London are seen as the strongest contenders. During her meeting with representatives of the fund, including its managing director Yasir al-Rumayyan, Mrs May discussed investment opportunities in British science and research projects, education and infrastructure.Aramco is an acronym for Arabian American Oil Company, as the company was founded by Standard Oil (now Chevron) after the US firm was given a concession to explore for oil in the 1930s. In the 1970s the Saudi government began buying up shares in the company until it owned it outright by 1980. It currently has capacity to produce 12 million barrels of oil per day, with rights to at least 260 billion barrels of recoverable oil owned by Saudi Arabia. Saudi Arabia’s state-owned oil company is being urged to use the London Stock Exchange for the huge share flotationCredit:TOBY MELVILLE/Reuters Show more Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.