Boris Johnson has confirmed the British Army is being used in the rollout of "rapid turnaround tests" for coronavirus.
Speaking during a live briefing where a national lockdown across England was announced, the Prime Minister said the tests will be used to reduce the prevalence of the virus, and tests of "whole cities" will be rolled out within days.
Mr Johnson added it is hoped the tests will "drive down the disease".
The Army has been brought in to assist with logistics, while a rollout programme could begin in a "matter of days".
"Over the next few days, weeks, we plan a steady but massive expansion in the deployment of these quick turnaround tests, applying them in an ever-growing number of situations from helping women to have their partners with them in labour wards when they’re giving birth, to testing whole towns and even whole cities," the Prime Minister said.
A Ministry of Defence spokesperson said: "The MOD is working hard to identify where it can most effectively assist other Government departments and civil authorities.
"Through the COVID Support Force, the Armed Forces have personnel including specialist planners, medics and logisticians ready to assist with the response to the outbreak."
It had emerged earlier this week that Armed Forces planners had been looking into how personnel could help with a coronavirus mass testing pilot.
The MOD declined to comment on specific locations, but stated military help was an option on the table.
The British Armed Forces have had a key role in the coronavirus response since the start of the pandemic, including running mobile testing sites and helping to build the NHS Nightingale hospitals.
During the peak of the military's response, 20,000 troops were at readiness as part of the COVID Support Force, with more than 4,000 of them deployed at any one time.
Since March 2020, the MOD has responded to 231 Military Aid to Civilian Authority (MACA) requests.
As of Friday 30 October, there were 547 military personnel assisting with 35 open MACA requests.
Recently, military medics have been sent to schools to trial COVID-19 tests that produce results in 30 minutes, while Royal Air Force personnel have been deployed to support coronavirus testing in Birmingham.
In Nottingham, military personnel are supporting in the coordination of a volunteer network which is helping to carry out the Drop and Collect self-test initiative.
Staff at the Defence Science and Technology Laboratory (DSTL) at Porton Down have also been assisting, providing advice and assistance, as well as a COVID-19 testing capability.