The UK has less than a week to reach its target of carrying out 100,000 coronavirus tests a day. But with its test booking website overloaded with requests within an hour of reopening on Saturday morning, can it scale up fast enough?
The UK was managing about 20,000 tests daily last week but ministers said there was more capacity going unused.
Now it has opened up testing to 10 million key workers and their families to ensure they do not have to self-isolate at home unnecessarily.
Greater testing could also inform decisions around social distancing and lockdowns, but tests are not available for the general public yet.