Unite has said that more than 2,800 of their members at four London NHS Trusts are to strike next month over a dispute in pay and staffing.
Strikes will hit Barking, Havering, Barts Health NHS Trust and Redbridge University Trust, East London Foundation Trust and Guys and St Thomas’.
Nurses, pathologists, caters, porters, cleaners will all strike between 13 and 22 September.
Unite general secretary Sharon Graham said: “NHS employers must stop sweeping the staffing crisis under the carpet. Hospitals are so short of staff that patients are frequently being put at risk.
“Until the fundamental causes of low pay and impossible working conditions are resolved, the problem is only going get worse.”