"At the start of the pandemic, if your firm moved to an alternative site or a working from home arrangement, we asked you to consider the broader control environment in view of the new circumstances," the Financial Conduct Authority said in guidance that was updated on Friday.
"Given the extensive duration of these arrangements, we now expect you to record all relevant communications (including voice calls) when working outside the office," it said.
Britain entered its first lockdown in March last year, and this week began a third lockdown as cases of coronavirus surged and the government told people to work from home if they can.
During the first lockdown, the FCA told bankers to continue to record calls, though noting that there may be some scenarios where this was not possible.
Working from home makes it harder for a banks' compliance officials to check that traders are not breaking rules, such as using personal phones for work-related calls.
The FCA began warning banks in October they must apply the same standards of surveillance and conduct to staff working from home or in the office.
(Reporting by Huw Jones; editing by David Evans)
By Huw Jones
