The number of confirmed coronavirus cases in the UK leapt to 35 after 12 new patients were identified in England.
Chief Medical Officer Professor Chris Whitty said three of the patients were close contacts of a known Covid-19 case that was transmitted within the UK - believed to be a Surrey resident.
Another new patient, from Essex, has no relevant travel to an affected area, Prof Whitty said yesterday.
He added investigations were ongoing as to whether the patient had contracted it "directly or indirectly" from an individual who had recently travelled abroad.
Of the eight remaining cases, six had recently travelled from Italy, while two had been in Iran.
These patients are from London, West Yorkshire, Greater Manchester, Hertfordshire and Gloucestershire. One of the confirmed cases is in Bury, according to Bury Council, which said the patient had been taken to a specialist NHS infection centre.
Dr Will Welfare, interim deputy director of health protection for Public Health England North West, said: "Public Health England is contacting people who had close contact with one of the latest confirmed cases of Covid-19. The case is a resident of Bury and became infected while in Italy. They are receiving care at an NHS specialist centre."
Of the three cases in West Yorkshire, two are residents of Leeds who became infected in Iran, while one is from Bradford who had been in Italy - the worst-affected country in Europe.
According to the director of public health for Hertfordshire County Council, two of the cases confirmed yesterday are from the county.
In a statement, Jim McManus said: "These new cases of coronavirus are nothing unexpected.
"We fully anticipate an increase in numbers which is why our services have planned for, and are ready for, this situation."
It comes after another patient was identified in Hertfordshire on Saturday.
All of the newly identified cases are being investigated and health officials have begun tracing anyone who had close contact with them.
As of 9am yesterday, more than 11,000 people had been tested for coronavirus in the UK - with 35 confirmed as positive.