PCR test appointments were temporarily unavailable in large parts of Scotland on Monday.
High demand led to slots on offer at only eight out of Scotland’s 56 walk-in test centres when checked on Monday afternoon.
At the same time, of the eight drive-through test sites north of the border only two – Glenrothes and Inverness – had appointments available on the day.
By Monday afternoon, walk-in slots were on offer for the same day at only Wick, St Andrews, Inverness, Kirkcaldy, Dunfermline, Aberdeen Strathdee, Oban and Galashiels.
Other centres showed the message: “There are currently no slots available on this day. Try again this evening, when more test slots will be made available.”
The lack of appointments comes as Scotland recorded its highest number of coronavirus cases since the start of the pandemic.
Provisional data released by the Scottish Government shows 8252 cases were recorded on Christmas Day, with 11,030 positive tests recorded on Boxing Day and 10,562 on Monday.
For some hours there were no walk-in PCR tests available to book in England on Monday due to a “high demand”, according to the UK Health Security Agency (UKHSA).
However, later on in the afternoon bookings were available in every region, with the UKHSA saying the reduced availability was merely “temporary”.
A UKHSA spokeswoman said: “Appointments for PCR tests are available, but high demand can lead to temporary reduced availability in some areas. More appointments are made available for people to book every afternoon.
“Testing is playing an integral role in keeping people safe and managing the spread of Covid-19.
“We are very grateful to everyone who is following the Government’s guidance and getting tested to protect themselves, their loved ones and their communities.
“Everyone with symptoms or who is directed to get a PCR test should continue to come forward to get a test delivered to their home or at a test site.”
A Scottish Government spokesperson said: “The PCR testing system continues to operate well even though we have seen significant increases in daily cases across the UK and our labs are working through cases as quickly as they can.
“If you have trouble finding an available test slot in your local area, we advise trying again later.
“The UK Government is responsible for capacity in the Lighthouse Lab network.
“Additional laboratory capacity has been implemented and we continue to work with the UK Government to ensure that the levels of lab capacity across the network remain appropriate.
“It is vital that test results are communicated in a timely manner to allow the appropriate public health action to be taken. We aim to have to communicate results from physical test sites within 48 hours.
“Postal tests may take longer to process given the added time taken to post to labs.”