Key workers trying to get a test for coronavirus are facing a longer wait after all of the slots were booked up within an hour of the government website reopening this morning.
It is the second day in a row that requests for home testing kits and appointments for drive-thru tests have had to be stopped because demand reached capacity in England and Wales.
There is still some availability for drive-thru tests in Scotland.
More bookings will be released throughout the day for those in England, the government has said, and bookings will reopen at 8am each day.
At least 10 million key workers and anyone in their households are eligible for coronavirus tests if they have symptoms of the illness.
Testing capacity was increased from 40,000 to 51,000 on Thursday, meaning the UK is "ahead of our plans" to reach 100,000 tests per day by the end of April, the government has said.
Here is a simple guide to who qualifies as a key worker, how they can book a test, and what it involves.
Who can be tested?
The government has said testing patients for the virus remains the priority.
However, in England key workers with symptoms of coronavirus and people who live with them and have symptoms can now be tested.
The government has said testing is most effective within three days of symptoms, a high temperature or a new continuous cough developing.
Employers have been able to register and refer key workers who are self-isolating since Thursday.
Who qualifies as a key worker?
The government has published a list of essential workers which includes all NHS and social care staff from doctors, nurses, midwives, paramedics, social workers and carers to support staff and supply chain workers.
Teachers, firefighters, local and national government staff, supermarket workers, police and delivery drivers are just some of the other roles included on the list.
Some utilities, communication and financial services staff are also included. The full list is here.
How do I arrange a test?
Essential workers can enter their details online here.
They will then receive an email or text the same day inviting them to book a test.
They will be able to choose between booking an appointment at one of more than 30 regional drive-through test sites or being sent a home test kit.
But the government has stressed kit numbers will initially be limited, so it is encouraging people to attend a regional test site if they can.
Mr Hancock said people who cannot go online can book a test through their employer.
Where will the tests take place?
The government says it is planning to have 50 drive-through testing sites by the end of April with the aim that most people will not have to drive for more than 45 minutes to get to a regional testing site.
A delivery service for home testing kits has been designed with industry partners, including Royal Mail and Amazon.
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A network of new mobile testing units designed by army engineers is being set up to travel to care homes, police stations, prisons and other sites where there is demand for testing.
Packages of satellite test kits will also be sent directly to care homes across England to enable testing of symptomatic residents.
What does the test involve?
The test involves taking a swab of the nose and the back of the throat, and can be done by the person themselves or by someone else.
What happens next?
Completed samples will be sent to a testing laboratory where they are analysed.
The government is aiming for test results from drive-through sites to be sent by text within 48 hours and home testing kit results within 72 hours of collection.
People will be given advice on any next steps that need to be taken after receiving their results.