Nearly 2,000 people a day are caught not wearing a mask on London buses, according to new figures.
Staff have stopped 53,900 travellers without mandatory face coverings on buses run by Transport for London (TfL) between 4 July and 2 August.
This includes 4,888 passengers stopped from boarding or ejected from a bus by compliance officers.
TfL said it was “a tiny proportion of the 70m journeys that have been made on busses” over the same period.
Siwan Hayward, director for compliance and policing at TfL, told the BBC: “We have actually seen really high levels of compliance in London.
“We have been educating customers of the need to wear face coverings over their nose and mouth, unless exempt, since June.”
Face coverings have been mandatory on public transport in England since 15 June.
But TfL did not enforce the rule for the “first few weeks” while the advertising campaign ran, Ms Hayward said.
Passengers without a covering are asked to wear one, or will face being refused on board or fined up to £100.
TfL said 244 of these penalty notices had been handed out.
Those who do not pay can be taken to court and fined up to £1,000.
People with certain health conditions, disabled people and children under the age of 11 will be exempt from the rule.
Tfl estimates “around one in 20 people” will have an exemption for medical reasons.
Compliance officers, with the power to stop and fine passengers, are now deployed to hotspots across the network.