A spokesman for Scotland Yard refused to comment on the arrangements but it is understood the prince had been told specialist officers will guard the family from when they arrive.
Harry and Meghan are flying in from their home in California with their own personal security detail but will become the Metropolitan Police’s responsibility when they land.
They are bringing their children, Archie, three, and Lilibet, who turns one on Saturday.
The Duke has been embroiled in a legal row with the Government over a Home Office decision to strip him of his UK security with his lawyers telling the High Court he was “unable to return home” over fears it is too dangerous.
It is only the second time Meghan has returned to the UK in more than two years since the couple quit their royal roles in 2020 and moved to the US.
The Sussexes will stay at Frogmore Cottage, their home near Windsor Castle.
The jubilee celebrations start on Thursday with Trooping the Colour but they will not take part in that after the Queen ruled only working members of the royal family will be allowed on the Buckingham Palace balcony for the traditional fly-past.
But they are expected at the service of thanksgiving at St Paul’s Cathedral on Friday and at some of the other key events over the weekend with a potential visit to the concert in front of Buckingham Palace on Saturday night.
They are also expected to throw a birthday party for Lilibet on Saturday, which may be attended by the Queen, who has never met her, but will not be carrying out any of their own engagements to avoid overshadowing the celebrations of the monarch’s seven decades-long reign.