Bookings for coronavirus tests for millions of key workers and their households have been halted for the day as a result of the 'siginificant demand.'
The Department of Health and Social Care apologised as no new tests were able to be booked from mid-morning on Friday as a result of demand.
It tweeted: "There has been significant demand for booking tests today. We apologise for any inconvenience.
"We are continuing to rapidly increase availability. More tests will be available tomorrow."
https://twitter.com/DHSCgovuk/status/1253627976442433537
One woman replied: "I had absolutely zero expectations of being able to book a test, and I can't. Just about sums this z-list government up."
Another said: "I put my details in and applied for a test (at at test centre) and was told I would receive a text shortly, that was early hours of this morning and I still haven’t received anything.
"I have symptoms and I am a keyworker and was wondering when I may receive my text?
The Department of Health tweet sought to assure the 10 million people in England now eligible for testing that more would be available tomorrow.
The government is scrambling to meet its daily 100,000 testing target by the end of next week in line with promises made by Health Secretary Matt Hancock.
On Thursday evening, Mr Hancock announced that people whose work is critical to the Covid-19 response, and those they live with, will be able to register for a test if they have symptoms, such as a high temperature or a continuous dry cough.
NHS and social care staff, police officers, teachers, social workers, undertakers, journalists and those who work in supermarkets and food production and essential utilities are among those now eligible along with those working in childcare.
At Thursday's daily Downing Street briefing, Mr Hancock said the move was "part of getting Britain back on her feet".
People will then receive a text message or an email with an appointment at a drive-through centre or they can request a home test kit, although the latter are currently in limited supply.
A help desk has been established to aid the process, while mobile units run by the Army are travelling around the country to where they are needed, such as care homes.
Once completed, test results from the drive-through sites will be sent out by text within 48 hours, and within 72 hours of collection of the home delivery tests.
Mr Hancock said he wants to make it as "easy as possible" for people to get a test, with the UK's regional test locations growing as the crisis goes on.
He added more test sites are being set up each day, and officials are exploring other ways to ensure testing reaches those who need it most.
A week ago, testing was extended to all NHS and social care staff and voluntary workers, police, fire and rescue services, local authority staff, defence, prisons, probation staff and judiciary and frontline benefit workers.
