The daily ceremony will now be carried out without any music or pomp.
But military sentries will still be posted outside the Queen’s central London palaces, with the Grenadier Guards fulfilling the role at the moment.
An Army spokesman said: “An ‘Administrative Guard Mount’ is when the Old Guard hands over duties to the New Guard without music or ceremony and is a familiar occurrence when heavy rain falls or there’s a timing conflict with public events in the area.”
The move came as it emerged the Chief of Defence Staff ordered senior officers to be ready to join the coronavirus fight by mid April.
In a memo, General Sir Nick Carter told them the killer bug’s spike is expected “in late May and early June”.
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The MoD revealed 20,000 troops are being put on standby to help ferry key supplies around the country and take over police duties.
But Downing Street insisted the soldiers will not be deployed onto the streets to keep public order.