Donald Trump thinks Andrew Mountbatten-Windsor's arrest was a "very sad thing"

The 79-year-old president said: "I think it's a shame. I think it's very sad. I think it's so bad for the royal family. It's very, very sad. To me, it's a very sad thing."

Trump also confirmed that King Charles is set to travel to the US "very soon", amid speculation that he will receive a state visit in the spring.

Meanwhile, Thames Valley Police previously released a public statement, confirming that Mountbatten-Windsor had been released.

The statement read: "Thames Valley Police is able to provide an update in relation to an investigation into the offence of misconduct in public office.

"On Thursday we arrested a man in his sixties from Norfolk on suspicion of misconduct in public office.

"The arrested man has now been released under investigation.

"We can also confirm that our searches in Norfolk have now concluded."

King Charles, his older brother, subsequently insisted that the "law must take its course".

The 77-year-old monarch said in a statement: "I have learned with the deepest concern the news about Andrew Mountbatten-Windsor and suspicion of misconduct in public office. What now follows is the full, fair and proper process by which this issue is investigated in the appropriate manner and by the appropriate authorities. In this, as I have said before, they have our full and wholehearted support and co-operation.

"Let me state clearly: the law must take its course.

"As this process continues, it would not be right for me to comment further on this matter. Meanwhile, my family and I will continue in our duty and service to you all."

Elsewhere, Oliver Wright, the Assistant Chief Constable at Thames Valley Police, said: "It is important that we protect the integrity and objectivity of our investigation as we work with our partners to investigate this alleged offence.

"We understand the significant public interest in this case, and we will provide updates at the appropriate time."