AS IT HAPPENED: Andrew Mountbatten-Windsor leaves police station; Former prince arrested at residence; King Charles says 'law must take its course'

We will pause our live rolling coverage of the dramatic arrest - and release - of former prince Andrew Mountbatten-Windsor.

The disgraced royal was held in police custody in Norfolk for almost 12 hours as officers interviewed him over allegations of misconduct in office, likely stemming from claims he sent confidential state information over emails to New York financier Jeffrey Epstein and others in the early 200s.

No charges were laid and Andrew was ferried back to Sandringham Estate under the gaze of the world's media.

While our live blog may be pausing, our coverage is not: You can read more on what Andrew's potential charge may be, the penalties that could await him and how this affects the UK's royal succession plan.

Thank you for reading. You can find all the latest news on Nine.com.au and 9News.com.au.

Andrew was released around 11 hours after his arrest, but still under investigation, meaning he has neither been charged nor exonerated. He was photographed slouched in the back of a vehicle as he left Aylsham police station.

While at the station, Mountbatten-Windsor is likely to have had his mug shot taken before being placed in a small prison cell ahead of his formal police interview. It's not known whether Mountbatten-Windsor said anything beyond "no comment" to each question posed — as is his right.

Searches were carried out at addresses in Berkshire, west of London, and Norfolk, northeast of the capital. Police said they had finished searching Mountbatten-Windsor's home, but officers were still searching his former residence near Windsor Castle.

The Crown Prosecution Service will ultimately make a decision about charging him.

Andrew Gilmore, a partner at Grosvenor Law, said that prosecutors will apply the two-stage test known as the "Code for Crown Prosecutors."

"That test is to determine whether there is a more realistic prospect of a conviction than not based on the evidence and whether the matter is in the public interest," he said. "If these two tests are met, then the matter will be charged and proceed to court."

Andrew Mountbatten-Windsor could face life imprisonment if he is charged with misconduct in public office, but a legal expert warns it is a difficult offence to prove.

The disgraced former prince has been released from about 11 hours of custody pending an investigation into suspicion of misconduct in public office after he was arrested at his Sandringham home about 8am today (7pm AEDT yesterday).

Loughborough University's expert in public law Dr Tom Frost said Mountbatten-Windsor was likely interviewed under police caution.

Read the full story here.

Andrew Mountbatten-Windsor was processed like any other prisoner while in police custody.

That does include, apparently, having his fingerprints taken and posing for a mugshot.

Thames Valley Police have not posted the mugshot online, as they do not identify people on arrest.

And all things considered, it's unlikely Mountbatten-Windsor will seize the opportunity to monetise it, as US President Donald Trump did with his own mugshot.

UK media has also reported, citing sources close to the remaining royals, that public funds will not be used in Mountbatten-Windsor's defence.But as he has not yet been charged, that's clearly a matter yet to be finally confirmed.

The operation to arrest Andrew Mountbatten-Windsor was carefully planned and in motion for weeks.

Police aimed to ensure they could take the former prince into custody and search several properties for potential evidence.

Take a look inside the delicate police operation here.

A politics expert says there could be a lot more to come out of Mountbatten-Windsor's arrest and the ongoing investigation.

"My reaction was actually one of sadness, because it wasn't the exploitation of girls that led to this, it was of course money and secrets," The Australia Institute's Amy Remeikis (pictured) told Today Extra.

"I think the Palace knew this was coming and it's one reason why he was dropped from all official royal duties."

She warned that the fallout from the ongoing investigation could spread far beyond Mountbatten-Windsor, suggesting other high-profile figures could be implicated.

"I think what's really going to be interesting is to see who he brings down with him from the UK establishment," she said.

"If there's one thing a royal knows, it's where the bodies are buried and how to use it."

The charge of misconduct in public office is an old one in the UK, dating back to at least the 18th century.

The offence has been noted as extremely hard to define and a high evidential bar for prosecutors to clear.

The Crown Prosecution Service says the offence is committed when a public officer acting as such wilfully neglects to perform their duty and/or wilfully misconducts themselves to such a degree as to amount to an abuse of the public's trust in the office holderwithout reasonable excuse or justification.

Andrew Mountbatten-Windsor's role as a UK trade envoy in the 2000s will be what prosecutors will point to as a "public office" if any charges are laid.

Notably, no politician in the UK has ever been successfully convicted of the offence, though over the years several have been charged.

Royals expert and associate editor for the Daily Mirror Russell Myers has been speaking to Today this morning about Mountbatten-Windsor's arrest, and did not hold back about what implications it held.

"The word 'unprecedented' has been used a fair few times over the last few years when we've been discussing big moments within the royal family," he said.

"But this is truly, truly extraordinary."

He said the arrest had come as a shock even to experienced royal-watchers.

"The veil of protection from the royal family and indeed the establishment has been wiped out completely," he said.

Myers said insiders had previously spoken discreetly about the then-Prince Andrew's reputation as a "bully".

"(It was) very, very difficult to find anyone who, even before this scandal really reared its head, really had a good word to say about him," he said

Mountbatten-Windsor's arrest has made worldwide headlines - but it wasn't completely out of the blue.

Multiple police agencies had previously confirmed investigations into the former prince, including his dealings with sex offender and financier Jeffrey Epstein.

Mountbatten-Windsor has consistently denied any wrongdoing.

For a full timeline of the events leading up to last night's dramatic arrest, spanning over 20 years, you can whip through this article by nine.com.au's Karishma Sarkari.

The journalist who conducted then-Prince Andrew's infamous 2019 TV interview says she is "stunned" by news of his arrest.

"I just have to say this doesn't happen in our country," Emily Maitlis, formerly of BBC Newsnight, told ABC radio this morning.

"The last time a royal was arrested was King Charles the First in 1647, and he was beheaded, and that was briefly the end of the monarchy.

"So to say that this is a crisis moment, I think, doesn't begin to cover it."

Maitlis' interview with Mountbatten-Windsor was itself a landmark moment for the royal family, which saw the then-prince publicly address his association with Jeffrey Epstein for the first time, and to deny all accusations of wrongdoing.

Mountbatten-Windsor was widely derided afterwards for his awkwardness facing the questions, and making bizarre claims including that he was incapable of sweating.