Andrew Mountbatten-Windsor has been released under investigation following his arrest on suspicion of misconduct in public office.

On Thursday morning, Thames Valley Police said it had arrested a man in his 60s in Norfolk and was carrying out searches at addresses in Berkshire and Norfolk.

King Charles III said the "law must take its course" in response to Andrew's arrest and that the police had his "full and wholehearted support and co-operation".

Police had previously said they were considering investigating Andrew over allegations relating to his association with the late sex offender Jeffrey Epstein and were reviewing allegations he shared confidential material.

Communications between the pair featured among the tranche of files released by the US government.

In an updated statement on Thursday evening, Thames Valley Police confirmed the man "had been released under investigation". It added that its searches in Norfolk had now been concluded.

The former prince was pictured slumped back in the back seat of a vehicle after leaving Aylsham police station.

This is the first time Andrew has been arrested. He has consistently and strenuously denied any wrongdoing.

Thames Valley Police said that, following a "thorough assessment", a formal investigation had now been opened.

It also said earlier in February that it was assessing a separate allegation that a second woman was sent to the UK by Epstein for a sexual encounter with Andrew in 2010. The woman, who is not British, was in her 20s at the time.

BBC News understands that Thames Valley Police contacted the Home Office to give them advance warning before Andrew Mountbatten-Windsor was arrested.

The arrest, which took place at Sandringham at 08:00 GMT on Thursday, is not in relation to any allegations of sexual offences.

Vehicles believed to be unmarked police cars were seen outside the King's Norfolk estate, where the former prince has been living since leaving his home in Windsor, in Berkshire.

The BBC understands that Royal Lodge - Andrew's former home in Windsor Great Park - is being searched by police. A number of uniformed officers have been seen beyond the gates.

Thames Valley Police said it was not naming the arrested man "as per national guidance", and warned that as the case was now active, care must be taken to avoid being in contempt of court.

Assistant Chief Constable Oliver Wright said: "We understand the significant public interest in this case, and we will provide updates at the appropriate time."

Norfolk Constabulary told the BBC it was "supporting a Thames Valley Police investigation into misconduct in a public office".

The former Duke of York served as the UK's trade envoy between 2001 and 2011, travelling globally and enjoying privileged access to senior government and business contacts around the world.

In 2010, Andrew appears to have forwarded government reports from visits to Vietnam, Singapore and China to Epstein, files relating to the late financier recently released by the US Department of Justice appear to show.

The documents also appear to show Andrew forwarded information on investment opportunities in gold and uranium in Afghanistan to Epstein.

Under official guidance, trade envoys have a duty of confidentiality over sensitive, commercial, or political information about their official visits.

King Charles said he learned of the news his brother's arrest with the "deepest concern".

"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," he said in a statement.

"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."

The BBC understands that the Prince and Princess of Wales support the King's statement.

It is also understood that neither the King nor Buckingham Palace were given advance warning of Andrew's arrest, which occurred on his 66th birthday.

The royals have been maintaining a business as usual approach, opting to continue with their engagements, despite the extraordinary developments of this morning.

The King, who had been attending a solo engagement to mark the start of London Fashion Week on Thursday, did not react to questions from reporters asking for his reaction to his brother's arrest.

Queen Camilla was asked about the arrest of her brother-in-law as she left an engagement in Windsor on Thursday.

"Are you concerned about Andrew's arrest, your Majesty?" the Queen was asked as she got into a waiting car outside a lunchtime orchestral concert at Sinfonia Smith Square Hall. She was seen waving but did not respond.

Andrew has always denied any wrongdoing over his association with Epstein. He has not responded to the BBC's requests for comment on the specific allegations in relation to the release of millions of Epstein files in January. (BBC)

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