Theresa May has acknowledged the "huge value" of the financial services industry to the UK following talks with bank bosses in Davos as the City braced for jobs being shifted from London after Brexit.
The Prime Minister said her talks with bankers and business chiefs at the World Economic Forum had been "positive" and insisted her vision of a "global Britain" would keep posts in the UK.
Bosses of JP Morgan, HSBC and UBS have all confirmed Britain's decision to scrap single market access will have major implications for their UK operations.
Speaking at the Swiss ski resort, where political and business leaders from around the globe have gathered, Mrs May said: "I've had positive meetings with bank CEOs here and also with CEOs from tech companies and others and the message I've brought here to Davos is that Britain outside of the European Union, we want to build a truly global Britain."
She added: "I value financial services in the City of London and I want to ensure that we can keep financial services in the City of London and that global Britain, I believe will do just that."
The Prime Minister told Bloomberg Television: "Financial services are of huge value to the British economy and of course the services that fit around the banks and asset management companies and insurance companies as well are important to us too.
"But as we look ahead to the Britain of the future, to the global Britain, to Britain outside the European Union, I want to ensure that we have that good relationship, good partnership with the EU, that we have negotiated a free trade agreement, which I believe will work for the UK but also for the European Union, that will ensure that stability and jobs and prosperity in the UK."
Her comments came following confirmation from bank chiefs that some parts of their businesses would be moved from the City in response to Brexit and Mrs May's decision to rule out single market membership.
Jamie Dimon, chief executive of US bank JP Morgan told Bloomberg: "It looks like there will be more job movement than we hoped for."
The lender employs 16,000 people in the UK, with London hosting its European headquarters, and has previously said around 4,000 jobs could go if Britain loses the right to sell financial services to the EU.
Mr Dimon said that number could rise or fall "depending on negotiations".
Goldman Sachs chief Lloyd Blankfein told the business broadcaster that New York is "already a bit of a gainer" from Brexit, as the bank eases up on previous plans to shift operations to Britain.
"Operating our business to maximise our global potential - we were trying to get as much into the UK as we could," he said.
"We're slowing down that decision."
But the US investment bank played down reports that the bank may cut London staff in half to around 3,000, while organising transfers to New York and to a new subsidiary in Frankfurt.
Stuart Gulliver, boss of British banking group HSBC, confirmed the bank is on course to move 1,000 jobs from its London office to France, where it already has a full service universal bank after buying up Credit Commercial de France in 2002.
Swiss bank UBS is also expected to shift jobs to the continent. Chairman Axel Weber told the BBC that about 1,000 of its 5,000 employees are currently involved in operations dependent on passporting rights.
Financial firms have been waiting to discover whether the UK can hold on to passporting rights, without which they could face significant barriers when attempting to trade with countries within the European single market.
Barclays' chief executive Jes Staley, meanwhile, confirmed the bank's commitment to Britain.
"We're going to have to make an adjustment to the Brexit move, but it's going to be an adjustment that will be manageable for Barclays, and will not threaten, I think, the centre of London, or London as a centre of finance for Europe, and will not threaten the activities of Barclays in London," Mr Staley told CNBC.
"We are a British bank, we are committed to the United Kingdom, so we'll be fine," he added.
The PM said: "I have had a very good, positive discussion with banks about the benefits of the City of London, about what it is that has brought them to the City of London and how we can continue to build on that for the future, and there are huge benefits for investment in the UK."