A staff member at the Transport for London head office has tested positive for Covid-19.
The office in Southwark has been deep-cleaned and was open today.
The employee did not have direct contact with passengers.
A TfL spokesman said: “We are following advice from PHE after a staff member tested positive.
“The safety of our staff and customers is our top priority, so we are taking all necessary precautions and a deep clean has taken place within the building used by the staff member.”
It came as Kensington and Chelsea was today revealed as the London borough with the most cases of coronavirus.
Figures from Public Health England showed there had been eight confirmed cases by yesterday out of the 51 in the capital.
PHE’s breakdown showed five cases in Ealing, four in Barnet and three in Brent, Hounslow, Lambeth, Lewisham, Southwark, Wandsworth and Westminster.
Most of the other 33 boroughs have one or two cases but Barking & Dagenham, Bexley, Croydon, Enfield, Greenwich, Haringey, Havering, Islington, Newham, Richmond, Sutton and Waltham Forest have zero so far.
The latest figures come as Prime Minister Boris Johnson gathered ministers for an emergency Cobra meeting to discuss the next steps to tackle the illness.
While some other European countries are cancelling mass gatherings or limiting the number of people who can attend big events, Culture Secretary Oliver Dowden said there are “no plans” for Britain to follow suit.
Mr Dowden insisted the Government is following the advice of health officials and, while the situation is kept under review, there is currently “no need” to cancel big events or for people to avoid museums or other public places.
The UK has 280 confirmed cases of Covid-19 and three people have died in UK hospitals.
