Downing Street adviser Dominic Cummings broke lockdown rules by leaving London to travel to his family's home in Durham, according to reports.
Here is a timeline of Mr Cummings' movements since lockdown.
Strict lockdown rules are imposed which mean people can only leave their houses for essential travel.
In a TV address to the nation, Boris Johnson says people must stay at home to curb the spread of coronavirus.
Boris Johnson and Health Secretary Matt Hancock are confirmed to have tested positive for coronavirus.
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Mr Cummings is seen running along Downing Street shortly after the prime minister posts a video saying he has contracted the virus.
Weekend of 28 and 29 March
Over this weekend, Mr Cummings is said to have developed coronavirus symptoms.
Downing Street confirms Mr Cummings is self-isolating after developing symptoms of the virus.
According to a joint investigation by The Guardian and the Daily Mirror, Mr Cummings travelled to his family's farm in Durham – and it was on this date that Mr Cummings' family were spoken to by the police.
A spokesperson for Durham Constabulary said: "On Tuesday, March 31, our officers were made aware of reports that an individual had travelled from London to Durham and was present at an address in the city.
"Officers made contact with the owners of that address who confirmed that the individual in question was present and was self-isolating in part of the house.
"In line with national policing guidance, officers explained to the family the arrangements around self-isolation guidelines and reiterated the appropriate advice around essential travel."
Mr Cummings is pictured in Downing Street after recovering from coronavirus.