Boris Johnson and London mayor Sadiq Khan appeared to blame one another after pictures showed London commuters crammed into Tube trains on Tuesday morning.
The prime minister announced a series of strict measures on Monday to tackle coronavirus, aimed at keeping more people at home unless they are classed as “essential” workers.
Transport for London (TfL) has cut services by 50% in recent days, which it claims has contributed to an 87% reduction in passenger numbers.
Images taken in central London after the lockdown started on Tuesday, however, showed hundreds of commuters standing and sitting in close proximity on Tube trains.
The mayor said in a statement on Tuesday that more needed to be done by employers to help alleviate the strain on the capital’s transport networks.
TfL – which is chaired by Khan – has suspended the Circle and Waterloo & City lines, and reduced frequencies on other parts of the Underground network.
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The mayor said “growing numbers” of TfL staff are off sick or self-isolating, which means “we cannot run more services than we currently are”.
He added that many people still travelling are on zero-hours contracts, work in the gig economy or are freelancers.
He said that a “proper package of support” from the government for these workers “would alleviate this situation”.
Johnson, however, raised concerns about cutbacks in London Underground services to explain the lack of available trains.
His official spokesman said both the PM and transport secretary Grant Shapps had spoken to the mayor.
The spokesman said: “The prime minister raised with the mayor the issue of reduced services on the tube and its impact on people trying to get to work. But this is a matter for TfL.
“The transport secretary has also spoken to the mayor of London on this issue where they discussed looking at ways to make sure appropriate timetabling is in place to ensure it is safe for those who need to get to work because they cannot do this from home.”
Health secretary Matt Hancock meanwhile said the Underground should be running “in full” to help commuters maintain social distancing and slow the spread the virus.
He said Tube trains should be operating at maximum capacity so people are “obeying the two-metre rule”
Hancock claimed there is “no good reason” why TfL reduced Tube train frequencies, and it should be running in full so passengers are “spaced out”.
He added: “We should have more Tube trains running.”
But a spokesman for Khan insisted ministers have been told “countless times” that TfL cannot run a full service due to levels of staff sickness and self-isolation.
TfL pledged to “continue to run as much of a Tube service as we possibly can”.