Actress Emma Thompson visited The Whittington Hospital and spoke of the “alarming” number of people with the disease in London.

She visited the mobile screening unit ‘Find & Treat’ at the hospital as part of Boris Jonhnson’s campaign to raise awareness after figures were released showing that London has the most cases of the disease than any other capital in Western Europe.

Thompson became TB ambassador in January 2015 and was accompanied on the visit by her son, Tindy, who was treated for TB in 2011.

She said: “Early diagnosis and treatment are vital in the fight against TB, a battle which I am deeply committed to after my son Tindy’s experience of the disease. The scale of TB in such a developed, world-class city as London is truly alarming and I will continue to work with the Mayor to keep this disease at the top of the health agenda.”

The visit is part of a project, commissioned by Public Health England, to develop a short film about the disease to encourage Londoners to get tested.

Boris Johnson said it was “essential” for Londoners to know the symptoms of this “debilitating disease”.

He said: “Whilst TB rates in London have dropped over the last three years, it is unacceptable that our great city still has some of the highest levels in Western Europe. The Find & Treat service is making a real difference by diagnosing and treating hard-to-reach communities across the capital. Emma and Tindy are doing a great job raising awareness of this illness and I urge all Londoners to remember that anyone can become infected with TB and to get tested if they have any concerns.”