Philip Hammond has been appointed Chancellor of the Exchequer by new Prime Minister Theresa May.
He leaves his position as foreign secretary to replace George Osborne, who is understood to have been told by Theresa May that he services were no longer required.
Mr Hammond has said he will not issue an emergency Budget later this year, as George Osborne had suggested in the event of a Brexit vote. However, the new Chancellor told the BBC the economy had suffered a "shock" following the decision to leave the European Union, and confidence had been "rattled".
On his first day in his new office, Philip Hammond said he would spend it holding meetings to assess "where the economy is".
"I believe it is now going to be incredibly important as we move forward from the historic decision that we have made to leave the European Union and try and build on that decision to stabilise our economy and then go forward to build a new future for Britain," he said.
Although Mr Hammond is known as a "fiscal hawk" - someone who believes in strong public finances, he is unlikely to be able 'balance the books' as quickly as George Osborne wanted. Launching her leadership campaign earlier this week, Theresa May said "we should no longer seek to reach a budget surplus by the end of the Parliament".
Having been Chancellor since 2010, often seen as David Cameron's right hand man, George Osborne took to Twitter to say it had been a "privilege", adding that "others will judge - I hope I've left the economy in a better state than I found it."