Campaigners from the group Republic have become much more vocal and visible in recent years, but the spraying of graffiti on an historic cathedral suggests a more aggressive approach from some who wish to have the monarchy abolished.

Red graffiti spelling out the words “Not Our King” was sprayed onto the perimeter wall of St Asaph Cathedral in north Wales, shortly before an Easter service there attended by King Charles and Queen Camilla.

It is not known who sprayed the graffiti, and Republic said it did not condone the action.

The Royal Maundy service is held at a different location around the country each year on the Thursday before Easter.

King Charles III shakes hands with some of the 77 men and 77 women Maundy recipients during the Royal Maundy Service at St Asaph Cathedral. Credit: PA

This was the first time the monarch has travelled to a Welsh cathedral on Maundy Thursday since 1982.

Workers in hi-vis jackets were seen attempting to remove the spray paint before the King and Queen arrived.

In the end, it was covered up with a tarpaulin sheet and a police van was parked in front of it.

It’s not known if the King and Queen saw the graffiti or were made aware of it before their arrival, but they would have heard the official protest from the Republic campaigners, who now gather at this event each year.

They brought their yellow flags and banners and chanted “Charles, what did you know?”, which is related to the ongoing investigation into Andrew Mountbatten-Windsor and his long friendship with the convicted sex offender Jeffrey Epstein.

The chief executive of Republic, Graham Smith said: “Charles shouldn’t be able to avoid questions about his complicity in the Andrew scandal. The public wants answers. That’s why activists were protesting in North Wales today.”

The graffiti was covered up before the King arrived. Credit: PA

Asked by ITV News for a response to the graffiti sprayed on the cathedral, Smith said he and the fellow protestors “do not condone graffiti, but it says something about changing attitudes that it would happen in a small place like St Asaph.”

North Wales Police said in a statement: “We are investigating an incident of criminal damage in the area surrounding St Asaph Cathedral. Graffiti appeared on the outside surrounding walls in areas open to the public during the early hours of today, 2 April. Denbighshire Council are in the process of removing the graffiti.”

Chief Inspector Caroline Mullen-Hurst from the force added: “Officers are conducting enquiries to establish the full circumstances and to identify the individual or offenders responsible. Such behaviour has no place in our community, and we are committed to ensuring that those responsible are held accountable.”

The first recorded Royal Maundy service was held in 1210 by King John and commemorates the Last Supper of Jesus Christ.

It set off a tradition of distributing alms by the monarch.

This year, King Charles gave recipients two purses: a white one including a set of specially minted silver Maundy coins totalling 77 pennies, to match the King’s age; a red purse containing a £5 coin marking 100 years since the late Queen’s birth and a 50p coin celebrating the 50th anniversary of The King’s Trust charity.

The Royal Family will next gather over the bank holiday weekend for the Easter Matins Service at St. George’s Chapel in Windsor on Sunday.

The King and Queen will attend with other members of the family, but the palace has said the daughters of the former prince Andrew, Princesses Beatrice and Eugenie, will not be there as they have made alternative plans with the agreement and understanding of the King.

Andrew Mountbatten-Windsor has consistently denied any wrongdoing in relation to his friendship with Jeffrey Epstein.

This is the Talking Royals – our weekly podcast about the royal family, with ITV News Royal Editor Chris Ship and Producer Lizzie Robinson…