Andrew Mountbatten-Windsor was arrested on his birthday Thursday on suspicion of misconduct in public office.

Police arrested the former Prince Andrew on Thursday on suspicion of misconduct while in office, following weeks of new revelations over his relationship with convicted sex offender Jeffrey Epstein.

The stunning development marks the first arrest of a member of the royal family in centuries and makes him the most high-profile figure to face criminal accusations in a scandal that continues to sweep in some of the world`s richest and most powerful.

The arrest comes after a remarkable fall from grace for the brother of King Charles III, who was stripped of his titles last year and is now known only as Andrew Mountbatten-Windsor - and is yet another blow to Britain`s already beleaguered royal family. The king expressed his "deepest concern" at the news Thursday and stressed that "the law must take its course."

Mountbatten-Windsor, who turned 66 on Thursday, has always denied any wrongdoing in connection with Epstein.

The Thames Valley Police said in a statement early Thursday it had arrested a man in his 60s on suspicion of misconduct in public office, which carries a maximum sentence of life imprisonment in the United Kingdom.

Andrew Mountbatten-Windsor is escorted by police from his residence on the Sandringham Estate in Norfolk, east England, on Thursday.Bav Media

The police force, which covers an area in southern England where Mountbatten-Windsor used to live, did not name him, as is standard practice under British law.

"We understand the significant public interest in this case, and we will provide updates at the appropriate time," Assistant Chief Constable Oliver Wright said. "Following a thorough assessment, we have now opened an investigation into this allegation of misconduct in public office."

Earlier this month, the Thames Valley Police said it was looking into a claim that the former prince, while serving as U.K. trade envoy in 2010, had shared confidential documents with Epstein.

One email in the latest U.S. release appears to show Mountbatten-Windsor forwarding Epstein a report from his special adviser about the then-prince`s visit to Southeast Asia.

Mountbatten-Windsor has not commented on the latest batch of files published by the Department of Justice.

His arrest caps years of growing pressure on Mountbatten-Windsor, the son of the late Queen Elizabeth II, over his yearslong friendship with Epstein.

Police said they were searching two addresses in Berkshire and Norfolk. Mountbatten-Windsor lived in Windsor`s Royal Lodge in Berkshire until earlier this month; his new home on the Sandringham Estate, a royal residence, is in Norfolk.

Earlier, news photographers captured what appeared to be unmarked police cars arriving at Mountbatten-Windsor`s home in Sandringham.

Norfolk police said in a statement that they were "supporting a Thames Valley Police investigation into misconduct in a public office."

A man steps out of an unmarked car at the former prince`s home on Thursday in Sandringham, Norfolk.Peter Nicholls / Getty Images

In his comments early Thursday, the king directly addressed the British public and signed the statement "Charles R" rather than the usual practice of issuing it through Buckingham Palace:

"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."

The scandal surrounding Mountbatten-Windsor has centered on the accusations of Virginia Roberts Giuffre, who alleged that she was trafficked by Epstein to his powerful friends, including the former prince.

Mountbatten-Windsor stepped back from active royal duties in 2019 and in 2022 reached a legal settlement with Giuffre for an undisclosed amount after she filed a lawsuit in 2021 alleging that the former prince sexually abused her when she was 17.

Mountbatten-Windsor has denied having had sex with Giuffre.

On Thursday, the Giuffre family released a statement responding to Mountbatten-Windsor`s arrest.

"Today, our broken hearts have been lifted at the news that no one is above the law, not even royalty," the family said. "For survivors everywhere, Virginia did this for you."

It is extremely rare for a senior member of the royal family - or someone who used to hold such status - to be arrested.

In 2002, Princess Anne, the sister of the king and Mountbatten-Windsor, was convicted under the Dangerous Dogs Act after her English bull terrier, Dotty, bit two children while walking in Windsor Great Park.

British media said at the time it was the first instance of a royal being convicted of a criminal offense, but she was not arrested.

"I can`t think of anything like this in modern times," the royal historian and author Sarah Gristwood told NBC News. "It is the first age in which someone who was very recently a senior royal could be treated like any other common criminal."

Plenty of senior figures were imprisoned in the times of royal families such as the Tudors and the Stuarts, who ruled between the 15th and 18th centuries, but only on political grounds, Gristwood said.

King expresses ‘deepest concern` over Andrew`s arrest