David Walton, a member of the Bank of England's Monetary Policy Committee (MPC), has died after a short illness.
David Walton inspired respect among colleagues, the Bank said
The MPC is responsible for setting UK interest rates, and last month it voted 7-1 to keep rates on hold at 4.5%.
Mr Walton, who was 43, was the sole member of the MPC to vote for an interest rate rise at its last meeting.
"It is with great sadness that the Bank of England has learnt that David Walton died yesterday evening, unexpectedly, after a short illness," the Bank said.
Mr Walton started his career as an economist at the Treasury and subsequently worked at the investment bank Goldman Sachs.
"All our thoughts are with David's wife, his young children and his parents," said Mervyn King, governor of the Bank of England, in a statement.
"David inspired the respect and affection of all his colleagues in the Bank and today's news has come as a shock to us all."
His death leaves the rate-setting committee with just seven members out of its normal nine.
A replacement for Richard Lambert, who left to join the Confederation of British Industry (CBI), is yet to be announced.
The MPC normally has four external members appointed by the chancellor and five from within the Bank of England.
It currently just has two external members, including David Blanchflower, professor of economics at Dartmouth College in the US, who attended his first meeting of the MPC last month.
Mr Walton was known as one of the key "hawks" on the MPC, who were pushing for higher interest rates because they feared that inflationary pressures were growing in the world economy.
Some analysts have been critical of the Treasury for the delay in filling the other empty positions on the MPC.