JP Morgan chief Dimon warns Hammond‎ over Brexit terms

One of Wall Street's top bankers has urged ‎Philip Hammond to ensure a long transition period for the UK's exit from the European Union amid warnings about "cliff-edge" disruption to financial markets.

Sky News can reveal that Jamie Dimon, the chairman and chief executive of JP Morgan, met ‎the Chancellor in Downing Street on Thursday, months after warning that Brexit could force him to move up to 4,000 jobs out of the UK.

The JP Morgan boss - who was reported by US media outlets to be under consideration as a candidate to become Donald Trump's first Treasury Secretary - is understood to have told Mr Hammond that a multi-year Brexit transition ‎is essential for major international banks.

It is the latest warning to senior ministers about the City's demands for post-Brexit arrangements, with the triggering of Article 50 by the end of March 2017 starting a two-year process for the UK's departure from the EU.

It is at least the third occasion in the last six months on which Mr Dimon has met ‎the UK's finance minister.

He enjoyed a close relationship with Mr Hammond's predecessor, George Osborne, warning shortly before June's referendum that JP Morgan would have to move between 1,000 and 4,000 UK-based jobs overseas if the UK left the EU.

Like other banks, JP Morgan has yet to finalise any relocation plans for UK-based staff, with major City firms awaiting the details of the Government's Brexit plans and the fate of Britain's access to the single market for financial services.

JP Morgan was also a significant donor to Britain Stronger in Europe, the lead campaign group for the UK's continued membership of the EU, writing a cheque for £500,000.

Other Wall Street banks, including Citi and Goldman Sachs (NYSE: GS-PB - news) , also made substantial donations.

Since the referendum, Mr Hammond has held a number of meetings with senior bankers, including an attempt to reassure them about the Government's attitude to the City during a visit to Wall Street last month.

JP Morgan declined to comment on Thursday, while the Treasury could not be reached.