Cabinet Office minister Michael Gove had to abandon a meeting with Boris Johnson and leaders of the devolved nations on Thursday after he was notified he may have come into contact with someone who had coronavirus on a trip to Portugal.
The Chancellor of the Duchy of Lancaster had gone to Porto with his son to watch the Champions League final between Chelsea and Manchester City.
Mr Gove has been alerted through the NHS app that he may have been in contact with someone who had the virus.
The Daily Mail reported that it is believed the contact happened on the flight home from Porto.
The Cabinet Office confirmed Mr Gove had been pinged by the app.
Mr Gove had been due to meet the first ministers of Wales, Scotland and Northern Ireland with the Prime Minister in a bid to strengthen the union.
Instead of self-isolating for 10 days, Mr Gove will be able to take part in a pilot scheme for workplaces, including No 10, where he can instead be tested every day for a week.