Three men have been arrested after "box-loads" of lateral flow tests meant for schools were stolen from a lorry.
The Covid-19 tests were taken from Harlow Business Park in Essex in the early hours of Tuesday.
Police said all of the tests were later retrieved.
A 31-year-old man from Canvey Island, Essex, and a 27-year-old man from Newham, east London, were arrested on suspicion of theft.
A 37-year-old from Dagenham, east London, was arrested for the same offence, as well as on suspicion of drug driving.
Ch Supt Stuart Hooper, from Essex Police, said: "Our colleagues in the NHS, and dedicated volunteers across the country, are working tirelessly to stop the spread of coronavirus and save lives.
"I'm thrilled that we were able to recover the lateral flow tests so that those in need are able to keep themselves and others safe at this difficult time."