The Queen will decamp to Windsor Castle, cancel her traditional garden parties and postpone investitures as the threat of coronavirus triggers a wholesale ripping up of the royal diaries for all members of her family.

Buckingham Palace announced that the monarch, who will be 94 next month, would be leaving Buckingham Palace on Thursday.

“Her Majesty will move to Windsor Castle for the Easter period on Thursday 19 March, one week earlier than planned. It is likely the Queen will stay there beyond the Easter period,” it said.

The precautionary measures follow the government’s announcement that the spread of coronavirus in London is thought to be some weeks ahead of the rest of UK.

Officials are concerned for the welfare of the Queen and the Duke of Edinburgh, 98, who since retiring spends his time on the Queen’s Sandringham estate in Norfolk.

The Duke and Duchess of Sussex are understood to be taking “appropriate measures” over coronavirus after suggestions that Prince Harry could have been exposed to it during his final UK engagements this month.

Harry hugged Formula 1 driver Lewis Hamilton as the two opened the Silverstone Experience Centre on 6 March.

Two days before, Hamilton was photographed at the WE Day UK charity events in London alongside the actor Idris Elba and Sophie Trudeau, the wife of the Canadian prime minister – both of whom have since tested positive for Covid-19.

The Queen has already cancelled planned engagements in Cheshire and Camden as a “sensible precaution” because of her propensity to attract crowds, and to prevent any drain on over-stretched services required to host such public events.

Following consultation between her medical household and the government, other events pencilled in for “the coming months” are also now being cancelled as part of unprecedented peacetime measures to try and control the spread of the virus. These include the Maundy service at St George’s chapel on 9 April.

“Three garden parties hosted by the Queen, due to be held at Buckingham Palace in May, will not now take place,” a Buckingham Palace spokesman said.

“Guests already invited to these garden parties will be asked to attend in 2021.

“Two additional garden parties given for the Not Forgotten Association and the National Trust will also not take place.” A decision is yet to be made on the annual garden party at the Palace of Holyroodhouse in Edinburgh.

The cancellation of the Queen’s garden parties is thought to be unprecedented. Palace officials could not recall a similar occasion in recent memory.

Trooping the Colour, one of the annual highlights of the royal calendar and one of the family events which the Prince Harry and Meghan were expected to attend, is also in doubt, as is the 75th anniversary of VE Day and the state visit by the Emperor and Empress of Japan. Further announcements on these “will be made in due course in consultation with the government”.

Buckingham Palace declined to comment on whether Harry and Meghan were self-isolating at their Vancouver Island retreat. One source said that the couple, like everyone, would be taking “appropriate measures and following government advice”. Should they be made aware of being in contact with someone who has tested positive, they would act accordingly.

Trudeau announced last week that she had put herself in quarantine, having been tested after experiencing mild symptoms on her return from London.

Elba revealed on Monday he had tested positive via a video on Twitter, in which he said he felt OK and that he had no symptoms but had decided to self-isolate. The Luther actor said he only got tested after coming into contact with someone who later confirmed they had coronavirus, but did not give details of who that person was.

Hamilton has urged fans to take coronavirus seriously, and has posted a video showing how to hand-wash on his Twitter account. It is not known if he has been tested for the virus.

Harry flew back to Canada just before Justin Trudeau announced the closure of Canada’s borders to stop the spread. Trudeau has urged Canadians to stay at home “as much as possible”.