Police have arrested a London Ambulance Service [LAS] contractor on suspicion of stealing face masks to sell online for exorbitant prices.
The man in his 20s also allegedly took other protective items from medical centres across north London.
The Metropolitan Police said he had access to the sites because he was a contractor working with LAS.
Staff tipped off officers after noticing their equipment stores had been depleted.
The suspect was arrested in north London in the early hours of yesterday morning.
Several of the items he is accused of stealing had already been offered online.
Investigators questioned the contractor working on hospital grounds at a police station before bailing him until the end of April.
Officers were able to recover a number of items during their searches and these have been returned to LAS.
Detective Inspector Jason Colby, leading the investigation said: "I am saddened that anyone would take advantage of the NHS for their financial gain at such a critical time.
"These masks are a vital piece of Personal Protective Equipment for emergency service personnel and are used to keep both themselves and patients safe.
"We will continue to crack down on anyone attempting to take advantage of our emergency services for personal gain, especially at such an unprecedented time.
"We are grateful to those who are assisting our investigation."