Parts of London have higher rates of tuberculosis than countries such as Rwanda, Eritrea and Iraq, according to a report.
The capital recorded more than 2,500 new cases of TB last year – about 40% of the UK’s total.
The report, by the London Assembly, found a third of London boroughs exceed the World Health Organisation’s (WHO) “high incidence” threshold of more than 40 cases per 100,000 people.
Of these, Hounslow, Brent, Harrow, Newham and Ealing have rates of more than 150 incidents per 100,000 people.
WHO figures from 2013 show Iraq has 45 per 100,000 while Rwanda had 69 and Eritrea 92.
As a whole, the UK had 13 cases per 100,000.
Tuberculosis is an infectious disease which is passed on through coughing and sneezing.
Most people who get it have had prolonged exposure to an infected person.
Prisoners, refugees, migrants, people with substance abuse issues and the homeless are most at risk.
The report calls for Londoners be educated about the disease and for the Greater London Authority to include TB services when dealing with rough sleepers.
Dr Onkar Sahota, chair of the London Assembly Health Committee, called the findings “astounding” and urged London mayor Boris Johnson to act.
Dr Sahota said: “If we don’t get a grip on London’s TB situation now, the harder and more expensive it will be to tackle in the years to come.
“With pressures on health budgets, we can’t afford to take our eye off the ball.
“The mayor needs to take more accountability for TB control in London.
“He is uniquely placed to drive forward measures for TB prevention, as well as better access to treatment.”
A City Hall spokeswoman said: “The Mayor takes the issue of TB seriously and recognises that it is a significant health challenge for London.
“Recent figures show that, in the three years to 2014, the number of people infected in the capital has fallen, but the Mayor remains committed to tackling TB and is assured by Public Health England that every effort continues to be made to prevent and treat the disease in London.”
Globally, nine million people fell ill with TB and 1.5 million died from the disease in 2013, according to WHO figures.
Aside from HIV/Aids, it is the greatest single infectious agent killer worldwide.
Swaziland in southern Africa had the highest rate of cases globally – 1,382 per 100,000 people.