A London Underground line has been suspended and dozens of trains cancelled in the north of England after staff shortages were triggered when workers were told to self-isolate by the NHS Covid-19 app.
The Metropolitan Line was not running on Saturday due to several control room workers being pinged. Services on the Piccadilly and District line were also affected.
Richard Jones, London Underground's head of network operations, said: "Due to a shortage of control room staff who are having to self-isolate following notification this morning via the Test and Trace app, there will be no service on the Metropolitan line for the rest of the day.
"This will also impact the Piccadilly line with no service between South Harrow and Uxbridge and no service on the District line between High Street Kensington and Edgware.
"Services are expected to resume on the Piccadilly and District lines at 9pm this evening. We apologise to customers for the disruption.”
Recommended Pingdemic ‘threatens food supplies’ amid warnings app is ‘losing social consent’
Meanwhile, in the north of England, several Northern railway services were cancelled or delayed between Huddersfield and Sheffield, Sheffield and Leeds, Retford and York, and Leeds and Doncaster.
It all comes amid ongoing warnings to the government over a so-called pingdemic – a surge in people, including medics and key workers, being forced into self-isolation by the app.
More than 530,000 self-isolation alerts were sent to app users in England and Wales during the first week of July. This represents a 46 per cent increase in the number of alerts compared to the previous week.
Transport unions have said the sheer levels of staffing disruption could result in "dire consequences" next week when all remaining restrictions are lifted just as infection rates are rising.
Mick Lynch, Rail, Maritime and Transport union general secretary, warned that Monday "will see a surge in workers pinged with a self-isolation instruction next week".