A senior executive at the Wall Street giant, Daniel Pinto, said that "hundreds" of staff may move to Dublin, Frankfurt and Luxembourg.

However, it is understood that the number of people who would be relocated involves between 500 and 1,000 jobs.

Earlier, Standard Chartered bank said it was in talks with German regulators about making Frankfurt its Europe base.

However, Standard said the impact on UK staff would be "minimal".

Several global banks have announced in recent weeks that they will move some jobs out of London as part of contingency plans for when the UK leaves the EU.

Speaking to Bloomberg News, Mr Pinto, head of investment banking at JP Morgan, said: "We are going to use the three banks we already have in Europe as the anchors for our operations.

"We will have to move hundreds of people in the short term to be ready for day one, when negotiations finish, and then we will look at the longer-term numbers."

JP Morgan's main offices in continental Europe are in Dublin, Frankfurt and Luxembourg, but it also has operations in Paris, Milan, Madrid and Stockholm.

JP Morgan is widely reported to be in talks to buy a Dublin office big enough to hold more than 1,000 workers.

Financial services shift

Since the Brexit referendum last year, European cities have lined up to try and woo financial services companies to move operations there to continue serving European clients.

Standard Chartered chairman Jose Vinals said on Wednesday: "We are looking at setting up a subsidiary in the EU to ensure we are prepared.

"The choice of Frankfurt is very natural as we have a branch there and we do euro clearing there."

However, a spokeswoman for the bank, which only has a small amount of business in Europe, said the impact on UK staff would be "minimal".

Other financial services companies have announced plans to move workers out of London in case the UK fails to secure "passporting" rights for them to operate across EU borders after Brexit.

Deutsche Bank said last week it could move up to 4,000 jobs out of the UK as a result of Brexit - nearly half its UK workforce.

Barclays told the BBC the bank was preparing to add hundreds of staff to offices in Dublin, Frankfurt and Milan to counter Brexit risks to its European business.

Contingency plans

Goldman Sachs has confirmed it will move jobs away from London and bulk up its European presence by "hundreds of people" before a Brexit deal is struck.

Insurers Lloyd's of London and Royal London are also setting up subsidiaries outside the UK.

JP Morgan's Mr Pinto told Bloomberg: "We have to plan for a scenario where there is no UK-EU passporting deal, and we have to move a substantial portion of our business to continue serving our European clients.

"We'll have to wait to see what kind of deal can be achieved and see what we need to do from there."

He was speaking on the sidelines of a conference in Saudi Arabia. A JP Morgan spokesman confirmed Mr Pinto's remarks, but did not elaborate on the story.

A report commissioned by the City UK industry group warned in October that as many as 75,000 financial services jobs could be lost from London if operations into the EU are severely disrupted after Brexit.