Passengers will have to start paying again from Saturday to use some buses, Transport for London (TfL) has said.
The need to tap in at the front of buses to pay for rides had been suspended during the coronavirus lockdown to protect drivers.
Reinstating bus payments is one of the conditions of a £1.6bn government bailout of TfL.
Twenty-nine London bus drivers have died after being infected with coronavirus, according to TfL.
Payments will resume on 85 routes run served by about 1,200 single-door and New Routemaster buses, and be rolled out to the rest of the TfL fleet of about 9,000 “once further safety measures have been introduced to protect bus drivers”.
TfL said on buses where payments will be required from Saturday, drivers’ protective screens have had the opening where cash was previously accepted sealed off, in addition to vinyl screens fitted last month to block communication holes.
Bus services were ramped up to 85% of normal frequencies this week and TfL is working towards reinstating 100% of its timetables “as soon as possible”.
TfL has introduced a “rigorous cleaning regime” across all its services, including buses and Tube trains.
This includes anti-viral fluid being sprayed inside areas used by passengers, and hand sanitiser dispensers being installed at bus stations and on Tube station platforms.
Passengers are being asked to avoid non-essential use of public transport and to use face coverings when using it.
A full list of bus routes affected from Saturday is available at tfl.gov.uk.