Randell was chair of the regulator for four years, and Lloyd will now act as chair until the Treasury appoints a permanent replacement.
The recruitment process is underway, the FCA said.
Lloyd joined the FCA Board in April 2019 and has been senior independent director, chair of the board risk committee and chair of the oversight committee.
Alongside his role at the FCA, Lloyd also chairs the Independent Parliamentary Standards Authority and is a council member of the Advertising Standards Authority. He was a founding trustee of the Money and Mental Health Policy Institute.
He led consumer watchdog Which as executive director from 2011 to 2016. And prior to this he was chief executive of the world federation of consumer organisations, Consumers International; head of policy at the housing charity, Shelter; and worked for two years in No10 Downing Street as a special adviser to the prime minister.
He was awarded an OBE in 2019 for services to the economy and consumer rights.
