(Left) Kate Middleton and Prince William attend the 2026 Commonwealth Day Service at Westminster Abbey in London on March 9, 2026; (Tight) Protesters outside the Commonwealth Day Service at Westminster Abbey on March 9, 2026.Credit : Karwai Tang/WireImage; Samir Hussein/WireImage

NEED TO KNOW

Members of the royal family faced protesters outside the Commonwealth Day service in London on March 9
The protesters held bright yellow signs referencing ex-Prince Andrew’s connection to the late Jeffrey Epstein, among other anti-monarchy messages
A palace insider tells PEOPLE that Andrew’s recent arrest is “much more serious” than past events that have rocked the monarchy

Kate Middleton, Prince William, King Charles and other members of the royal family faced protesters at their largest public gathering since the former Prince Andrew’s arrest.

On Monday, March 9, the royals attended the Commonwealth Day service at Westminster Abbey in London, where they were met with protesters from the anti-monarchy group Republic.

“What did you know?” spelled out a row of bright yellow posters held by the protesters, seemingly referencing Andrew’s connection to the late Jeffrey Epstein. Other signs held by the protesters included anti-monarchy messages and more references to the ex-Prince Andrew.

The Commonwealth Day service was the royal family’s largest gathering since Andrew, 66, was arrested on Feb. 19 on suspicion of misconduct in public office.

Andrew’s arrest in February — the first of a royal since 1649, when King Charles I was beheaded for high treason —  sent shock waves through the House of Windsor and raised questions about accountability and privilege.

“If it comes out that people knew stuff — whether it be members of the family or police or staffers — then heads must roll,” Robert Jobson, author of The Windsor Legacy, tells PEOPLE.

Graham Smith, CEO of the anti-monarchy group Republic, holds up the photo of Andrew Mountbatten-Windsor and Virginia Giuffre during a protest outside Westminster Abbey on March 9, 2026.Vuk Valcic/SOPA Images/LightRocket via Getty

A palace insider adds: “Other events have rocked the monarchy, but something from within — where someone is being arrested — is very different. This is much more serious.”

The former Duke of York, now called Andrew Mountbatten-Windsor, awoke alone at Wood Farm on the Sandringham estate on Feb. 19, where police officers arrived at his door.

Shortly after 8 a.m., authorities arrested King Charles’ brother on suspicion of misconduct in public office, linked to convicted sex offender Epstein, and drove him away in an unmarked car.

As news broke within the hour and images of police at Sandringham ricocheted around the world, Andrew’s family — led by the King — was learning of the arrest in real time.

Police officers stand guard near the entrance to Wood Farm, the home of Andrew Mountbatten-Windsor on Feb. 19, 2026 in Sandringham, Norfolk.Peter Nicholls/Getty

“This is the place where the Queen spent her last birthday in April 2022,” Jobson tells PEOPLE about the poignant place. “Four years later, it’s been raided by the police. It beggars belief.”

Andrew was taken to Aylsham police station in Norfolk, where he was read his rights and held for 11 hours before being released under investigation. Cameras captured him slumped in the back of an SUV as he left the station. “It is the ultimate humiliation,” a palace insider says.

The detainment came nearly four months after Andrew was stripped of his princely title and ordered to leave his longtime Royal Lodge home over his Epstein links in October 2025.

King Charles, 77, spoke out about the arrest in a brief statement: “I have learned with the deepest concern the news about Andrew Mountbatten-Windsor and suspicion of misconduct in public office… Let me state clearly: The law must take its course.”

According to Ailsa Anderson, former press secretary to Queen Elizabeth, the wording was deliberate.

“It was a way of distancing himself,” she says.

Prince Andrew and King Charles at the Duchess of Kent’s funeral in London on Sept. 16, 2025.Max Mumby/Indigo/Getty

As Andrew’s arrest reverberated beyond palace walls, attention turned to those closest to him. His ex-wife, Sarah Ferguson, who had lived with him at Royal Lodge and has not been seen in public since before Christmas, traveled abroad. The former Duchess of York faces renewed scrutiny over her past dealings with Epstein and whether she may be questioned in Andrew’s case.

Meanwhile, their younger daughter, Princess Eugenie, had been skiing with her husband and sons in­ Switzerland, while their elder daughter, Princess Beatrice, kept a low profile. Both sisters were reported to be “in a state” after their father’s arrest and made quiet public appearances in the weeks since.

“Their focus is on protecting their own children from this,” a source says.

Edoardo Mapelli Mozzi, Princess Eugenie and Princess Beatrice leave after attending the royal family’s traditional Christmas Day service in Sandringham on Dec. 25, 2025.Henry NICHOLLS / AFP via Getty

Released under investigation and without bail conditions, the late Queen Elizabeth’s second son faces an uncertain legal road. Andrew could remain in legal limbo for weeks or even months as police examine documents — released by the U.S. Department of Justice amid heightened scrutiny of those in Epstein’s orbit — that allegedly show that he shared information with Epstein secured during his work as the U.K.’s trade envoy.

Prosecutors, ultimately, will decide whether charges are brought. If he is convicted, misconduct in public office carries a maximum sentence of life imprisonment. The government is also reportedly considering legislation that would remove Andrew from the line of succession, where he currently stands eighth, behind Prince William and his children, and Prince Harry and his children.

As the investigation continues, focus is shifting inward.

“When these things went on, he was Prince Andrew, Duke of York — right at the heart of the royal family,” says Jobson. “The problem will be who knew what, when they knew it and why nothing was done.”