Prince Harry's attendance at King Charles' Coronation will have an impact on security measures - which will be assessed on a "case-by-case basis".
The Duke of Sussex will be part of the large congregation inside Westminster Abbey on May 6 watching his father and Queen Camilla being crowned - but he won't be with his wife.
Meghan Markle has decided to remain at home in California with their children, Prince Archie and Princess Lilibet, while her husband make a a 'fairly quick' trip to the UK next month.
Policing minister Chris Philp said he hopes the crowning of Charles and Camilla in just over three weeks' time will be similar in success to the "fantastic" handling of the late Queen's funeral and there will be a "huge policing operation".
Asked what effect Harry's presence will have on security measures at the coronation, Mr Philp told LBC: "Those obviously get assessed on a case-by-case basis."
On whether there will be a significant additional cost due to the duke's attendance, Mr Philp added: "I'm not going to get into people's individual protection arrangements but, by the way, we're providing protection for hundreds of foreign heads of state, overseas heads of state who are attending as well.
"It's a huge policing operation, both in terms of the streets and obviously protection for individuals, so it's a big operation."
He added: "We're going to make sure that everybody involved in the coronation, including the general public, are kept safe, obviously."
Mr Philp said police did a "fantastic job" at the late Queen's funeral, adding: "We're going to work to make sure we have a similar successful operation."
According to insiders, Harry was cutely aware that the historic occasion will be "pretty much the most important day" of the King's life.
It's claimed the duke decided to attend because he knew he would always have regrets if he turned down the opportunity to be at the Coronation.
A mass police presence will be out in force on the streets of central London as well-wishers flock to the capital to see the King and other members of the Royal Family.
The Metropolitan Police has yet to comment on the Coronation security arrangements.
Months ago, Harry was criticised for revealing in his memoir that he killed 25 Taliban insurgents while fighting in Afghanistan, with security experts suggesting it has made him and those associated with him targets.
Harry has been stuck in a long running dispute with the government over his security arrangements when back in the UK - and he has taken legal action against the Home Office.
The Duke of Sussex was told it would be up to the Home Office to decide what security was and wasn’t necessary after he stepped back from his duties as a working royal.
Whenever Harry has intended to return to the UK, he has been told to give 28 days notice so his security requests could be assessed, a condition which was first reported by The Telegraph.
He was reportedly left furious with the government department and demanded to know of anyone else with the same threat assessment that he had who had received no security after leaving public duty.
Harry also slammed the arrangements for his family’s June 2021 visit for the memorial events for his mum Diana as "patchy, disjointed and inadequate".
The duke won a judicial review against the Home Office's decision to deny his family automatic security in September 2021, but a date for the hearing has not yet been set.
Summarising Harry's claim against the Home Office, his lawyers said that he is "gravely concerned about his safety and security during future trips to the UK" and that he feels he was left with no choice but to take legal action "given the gravity of what is at stake for him and his family".
They continued: "The Duke and Duchess of Sussex have been subject to intense media scrutiny, hostile social media attention, and targeting by violent extremists due to (amongst other things) the [Duke's] ten years of military service in the British Army, the Duchess of Sussex's race and their involvement in charitable and other social justice initiatives."
His lawyers said the 28-day period, during which a decision would be made whether to give him security or not, could threaten his safety and created uncertainty for the family.
A Home Office spokesperson said the department does not comment on the individual security of members of the Royal family.
Harry isn't expected to stay in the UK for very long, as it's been reported he will only attend the Coronation ceremony itself and none of the other activities across the bumper weekend.
