'Our duty and service to you all': King Charles' telling words after former Prince Andrew's arrest

The British royal family are known to have the mantra "never complain, never explain", especially under the late Queen Elizabeth's reign.

However, following news of former Prince Andrew's arrest in Sandringham on his 66th birthday on Thursday morning (9pm AEDT), reigning monarch King Charles issued a strongly worded statement.

He acknowledged his "deepest concern" over an investigation into whether his younger brother had been involved in misconduct in public office by passing sensitive documents to Jeffrey Epstein during his time as UK trade envoy.

The King said authorities have his "full and wholehearted support and co-operation", while stating "the law must take its course".

But it was his final sentence which truly indicated the royal family's plans moving forward.

And like his late mother, His Majesty indicated he planned to put duty and service before all else.

"My family and I will continue in our duty and service to you all," he said, before signing off.

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And just hours later, the "keep calm and carry on" adage of the royals came into effect, with Queen Camilla the first to step out in London.

King Charles also received credentials at St James' Palace before opening London Fashion Week for the very first time, where he didn't answer any questions from waiting media.

Princess Anne, in a case of unfortunate timing, was due to visit a prison in Leeds during a packed itinerary in Yorkshire.

Often considered the hardest-working royal, Anne was also visiting a textiles factory, occupational therapy clinic and carers support organisation during the day in Northern England.

While the King was quick to release a statement, the Prince and Princess of Wales have not said anything publicly but it's understood they support His Majesty's statement.

We're also not expecting to hear anything from Mountbatten-Windsor, his ex-wife Sarah Ferguson or their two daughters, Princess Beatrice and Princess Eugenie.

'King has tried to get ahead of it'

Despite Buckingham Palace and King Charles not receiving any advance warning of Mountbatten-Windsor's arrest, they reacted by keeping planned engagements.

The monarch was quick to issue his statement in the hopes of quelling questions - and hecklers - while the royals continue their work.

"I think now the King has tried to get ahead of it with this statement," Telegraph UK's India McTaggart told the BBC.

"He can do little else, and we need to see how it unfolds, as Andrew is being questioned properly on this."

Royal commentator Katie Nicholl told the BBC the King had been waiting for this next step after police had stated they were investigating the claims against the 66-year-old.

"I suspect there is probably also a sense of relief on the King's part," the Vanity Fair correspondent said.

"I was told by sources close to the King this felt like a pressure chamber, just waiting for this arrest to happen."

Nicholl said while she was surprised by the King's strong statement, she believes the monarch was aware of the need for "greater transparency now around this".

"When you look at this statement, the King just couldn't keep silent," she said.

"I think when you consider the last reign, that of the late Queen Elizabeth, that famous mantra the late Queen had 'never complained, never explain' that simply doesn't wash here, that's simply not going to be enough of people.

"We're in a different era, we're in a different generation."

However, anti-monarchy group Republic doesn't feel the King's statement goes far enough and is calling on Charles and William to front the media.

"The silence from the Palace is deafening," Republic chief executive Graham Smith said in a statement.

"So far it's only been a couple of journalists and a number of hecklers who have challenged the royals directly. That has to change. Now."

Smith believes the monarch and his heir "must address what they knew and when, how Andrew's conduct was unreported for so long".

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