Firms are already on the hunt for the 'new London' after the decision for the UK to leave the EU has left many businesses wondering over their future in the capital.

As many as one in five businesses surveyed by the Institute of Directors are considering moving some of their operations outside the UK.

Vodafone, the seventh biggest company on the FTSE 100, has cast doubt over whether it will continue to keep its group headquarters in Paddington if it will no longer have access to the single market. The company said its Vodafone UK headquarters in Newbury were not affected.

“It remains unclear at this point how many of those positive attributes will remain in place once the process of the UK's exit from the European Union has been completed,” a spokesman said.

Goldman Sachs, the US investment bank, is also not ruling out a move.

Richard Gnodde, the co-head of the investment banking division of Goldman Sachs, said that “every outcome is possible” when asked if the bank plans would involve moving some of its employees to Eurozone cities in the wake of the EU referendum.

Future of British people living in Europe not secure, admits Cameron

Many other firms have reiterated their commitment to stay - at least for now.

Jes Staley, the chief executive of Barclays, has said the bank has no plans to move people out of the UK because of Brexit.

Meanwhile Douglas Flint, chairman, told City executives that the referendum result would not trigger another review into whether to move HSBC overseas. A review that concluded in February said that HSBC should stay put.

These companies have good reasons to stay.

London has frequently topped the rankings of the best global cities to do business in. It was named the best city in the world for businesses by the City Moment Index in January for its economic growth and real estate structure.

London was pulling ahead of New York as recently as March, when Deloitte declared that London's 1.71 million skilled jobs showed that it was growing faster than anywhere else in the world.

London is frequently cited as the top global city because it speaks English, the language of business. It is perceived as being soft on regulations governing business, meaning there are fewer barriers. And it is culturally rich, with excellent museums, restaurants, schools and other services that attract businesspeople from abroad.

But it is likely to be harder for London-based businesses to serve European markets after Brexit.

London is likely to lose its dominance in euro-denominated wholesale banking, or banking to mortgage brokers, mid-sized companies and real estate companies in euros. Many Eurozone companies and institutions have long wanted this activity to move to the Eurozone and be overseen by the ECB.

It might also lose its dominance in derivatives, a highly portable financial industry, if clearing houses are moved to Europe. Clearing houses in London stand between the buyers and the sellers of derivatives trades in a global market worth $493 trillion. They have become a vital safeguard to protect traders since the Lehman Brothers collapse in 2008.

6 ways Britain leaving the EU will affect you Show all 6 1 /6 6 ways Britain leaving the EU will affect you 6 ways Britain leaving the EU will affect you More expensive foreign holidays The first practical effect of a vote to Leave is that the pound will be worth less abroad, meaning foreign holidays will cost us more nito100 6 ways Britain leaving the EU will affect you No immediate change in immigration status The Prime Minister will have to address other immediate concerns. He is likely to reassure nationals of other EU countries living in the UK that their status is unchanged. That is what the Leave campaign has said, so, even after the Brexit negotiations are complete, those who are already in the UK would be allowed to stay Getty 6 ways Britain leaving the EU will affect you Higher inflation A lower pound means that imports would become more expensive. This is likely to mean the return of inflation – a phenomenon with which many of us are unfamiliar because prices have been stable for so long, rising at no more than about 2 per cent a year. The effect may probably not be particularly noticeable in the first few months. At first price rises would be confined to imported goods – food and clothes being the most obvious – but inflation has a tendency to spread and to gain its own momentum AFP/Getty Images 6 ways Britain leaving the EU will affect you Interest rates might rise The trouble with inflation is that the Bank of England has a legal obligation to keep it as close to 2 per cent a year as possible. If a fall in the pound threatens to push prices up faster than this, the Bank will raise interest rates. This acts against inflation in three ways. First, it makes the pound more attractive, because deposits in pounds will earn higher interest. Second, it reduces demand by putting up the cost of borrowing, and especially by taking larger mortgage payments out of the economy. Third, it makes it more expensive for businesses to borrow to expand output Getty 6 ways Britain leaving the EU will affect you Did somebody say recession? Mr Carney, the Treasury and a range of international economists have warned about this. Many Leave voters appear not to have believed them, or to think that they are exaggerating small, long-term effects. But there is no doubt that the Leave vote is a negative shock to the economy. This is because it changes expectations about the economy’s future performance. Even though Britain is not actually be leaving the EU for at least two years, companies and investors will start to move money out of Britain, or to scale back plans for expansion, because they are less confident about what would happen after 2018 AFP/Getty Images 6 ways Britain leaving the EU will affect you And we wouldn’t even get our money back All this will be happening while the Prime Minister, whoever he or she is, is negotiating the terms of our future access to the EU single market. In the meantime, our trade with the EU would be unaffected, except that companies elsewhere in the EU may be less interested in buying from us or selling to us, expecting tariff barriers to go up in two years’ time. Whoever the Chancellor is, he or she may feel the need to bring in a new Budget Getty Images

Where would they go?

"The most likely beneficiaries in the EU are Paris, Frankfurt, Amsterdam and Dublin," Greg Irwin, chief economist, if a report released by Global Counsel.

"But they cannot replicate overnight the advantages of the London ‘ecosystem’ supporting financial services, including skilled staff, legal services and market infrastructure," he said.