Thousands of troops are to be stood down from the 'COVID Support Force' (CSF) by the Ministry of Defence.
It means more than 20,000 troops who have been on high readiness since March in response to the coronavirus pandemic will be reduced to 7,500.
The figure will be kept under review as the COVID-19 response continues, while the 12,500 being released from the CSF will return to their normal duties.
Armed Forces personnel from all three services were put on alert in March and have been on standby throughout the coronavirus crisis as part of the deployed to assist with open military aid to the civil authorities (MACA) requests.
Despite the reduction, defence medics will continue to offer direct medical assistance, while other personnel will deliver PPE and maintain the national coronavirus testing capacity.
This week, the CSF began delivering testing kits to care homes using 20 specially designated vehicles, having already delivered more than 29,000 to 190 facilities.
Forces allocated to defence outputs such as counter-terrorism operations and the Continuous At Sea Deterrent will remain available at extremely high readiness, if required.
The Aviation Task Force, a tri-service dedicated helicopter capability during the COVID-19 pandemic, will be "restructured", however.
Meanwhile, 2,000 reservists who volunteered for mobilisation during the coronavirus crisis, but are no longer required to fulfil military aid to the civil authorities (MACA) tasks, are also being made part of the demobilisation process.
Minister for the Armed Forces James Heappey told Forces News: “For the last few months, we’ve had 20,000 soldiers, sailors, airmen, airwomen at relatively high-readiness in case we’ve been needed to respond in the tens of thousands to COVID-19.
“That hasn’t proven to be necessary.
"And whilst those troops will still be available, should the Government ask for them, the reality is, that holding people at readiness means that they can’t get on with other tasks, and it’s those training tasks that we need to get people now back on to."
He added: "Who knows what exactly we might be asked to do, but that's what makes our Armed Forces so amazing.
"Right now, they are out in aprons and masks helping to swab and do tests for COVID, but by next January they could be in a country that isn't even on our radar right now, doing something profoundly different".
Members of the British Army, the Royal Air Force and the Royal Navy have played a key role in the fight against COVID-19, with around 4,000 each day being deployed.
Military personnel were involved in the construction of the NHS Nightingale field hospitals set up across the country.
They have also been helping deliver PPE and conducting testing at mobile units.
Cover image: Royal Marines from 42 Commando helping administer COVID-19 tests at a mobile testing unit in April (Picture: MOD).