Princess Eugenie’s wedding is stretching public support for the royal family “to breaking point”, campaigners have claimed, after nearly 50,000 people signed a petition protesting the cost to taxpayers.

Friday’s wedding, expected to leave police with a security bill of about £2m, could “damage the royals for a long time to come,” warned anti-monarchy pressure group Republic.

Eugenie is to marry long-term boyfriend Jack Brooksbank, a tequila brand ambassador, in a lavish ceremony in Windsor.

The cost of the wedding itself will be covered by the royal family, but the bill for policing, traffic management and stewarding will be picked up by the taxpayer.

Thames Valley Police is to deploy armed officers, specially trained search dogs, mounted horses, and high-visibility patrols in a major operation.

Eugenie and Mr Brooskbank will take a 1km open-topped carriage ride to Windsor following the ceremony at Windsor Castle’s St George Chapel. The decision has raised eyebrows because it requires road closures and will significantly increase the force’s costs.

Police will be using automatic number plate recognition technology and CCTV to monitor traffic and people entering the area, and has set up barriers to safeguard against vehicle attacks.

Princess Eugenie marries Jack Brooksbank - in pictures Show all 40 1 /40 Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie and Jack Brooksbank kiss as they leave St George's Chapel after their wedding at Windsor Castle AP Princess Eugenie marries Jack Brooksbank - in pictures US actress Liv Tyler, her husband Dave Gardner, Kate Moss and her daughter Lila attend PA Princess Eugenie marries Jack Brooksbank - in pictures The bridesmaids arrive for the wedding of Princess Eugenie to Jack Brooksbank at St George's Chapel in Windsor Castle. PA Princess Eugenie marries Jack Brooksbank - in pictures Jack Brooksbank arrives ahead of the wedding of Princess Eugenie of York and Mr. Jack Brooksbank at St. George's Chapel on October 12, 2018 in Windsor, England. Getty Images Princess Eugenie marries Jack Brooksbank - in pictures British model Naomi Campbell arrives AFP/Getty Images Princess Eugenie marries Jack Brooksbank - in pictures The Duke of York and Princess Eugenie arrive for her wedding to Jack Brooksbank at St George's Chapel in Windsor Castle. PA Princess Eugenie marries Jack Brooksbank - in pictures Stephen Fry, right, arrives with his husband Elliott Spencer AP Princess Eugenie marries Jack Brooksbank - in pictures Sarah, Duchess of York, arrives for the wedding of Princess Eugenie and Jack Brooksbank at St George's Chapel in Windsor Castle, Windsor. PA Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie arrives accompanied by the Duke of York, at St George's Chapel for her wedding to Jack Brooksbank in Windsor Castle. PA Princess Eugenie marries Jack Brooksbank - in pictures WINDSOR, ENGLAND - OCTOBER 12: Prince Andrew, the Duke of York arrives with Princess Eugenie for her wedding to Jack Brooksbank at St George's Chapel in Windsor Castle on October 12, 2018 in Windsor, England. (Photo by Victoria Jones - WPA Pool/Getty Images) BESTPIX WPA Pool Princess Eugenie marries Jack Brooksbank - in pictures Demi Moore attends the wedding Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie of York arrives for her marriage to Jack Brooksbank at St George's Chapel, Windsor Castle, near London REUTERS Princess Eugenie marries Jack Brooksbank - in pictures The Duke of York walks his daughter Princess Eugenie down the aisle for her wedding to Jack Brooksbank at St George's Chapel in Windsor Castle, REUTERS Princess Eugenie marries Jack Brooksbank - in pictures The bridesmaids and page boys, including Prince George and Princess Charlotte, arrive for the wedding PA Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie of York passes her bouquet to bridesmaid Savannah Phillips during her wedding to Jack Brooksbank at St. George's Chapel on October 12, 2018 in Windsor, England. 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Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie of York and Mr. Jack Brooksbank are married by Dean of Windsor, David Conner at St. George's Chapel on October 12, 2018 in Windsor, England. Getty Images Princess Eugenie marries Jack Brooksbank - in pictures A Royal fan smiles outside Windsor Castle AP Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie of York and Mr. Jack Brooksbank are married at St. George's Chapel on October 12, 2018 in Windsor, England. Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Guests at the wedding ceremony of Princess Eugenie to Jack Brooksbank at St George's Chapel in Windsor Castle. PA Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie and her husband Jack Brooksbank, during their wedding ceremony at St George's Chapel in Windsor Castle. PA Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie and Jack Brooksbank walks down the aisle of the Quire after they were married PA Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie of York and her husband Jack Brooksbank emerge from the West Door of St George's Chapel AFP/Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie and her new husband Jack Brooksbank kiss as they leave St George's Chapel in Windsor Castle following their wedding. PA Princess Eugenie marries Jack Brooksbank - in pictures PABest Autumn Phillips, with Peter Phillips, Zara Tindall, and Mike Tindal, hold onto their hats as they arrive for the wedding of Princess Eugenie of York and Jack Brooksbank in St George's Chapel, Windsor Castle. PRESS ASSOCIATION Photo. Picture date: Friday October 12, 2018. See PA story ROYAL Wedding. Photo credit should read: Alastair Grant/PA Wire Alastair Grant PA Princess Eugenie marries Jack Brooksbank - in pictures Queen Elizabeth II and Prince Philip, Duke of Edinburgh look on after the wedding Getty Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie and her new husband Jack Brooksbank leave St George's Chapel in Windsor Castle following their wedding. PA Princess Eugenie marries Jack Brooksbank - in pictures Britain's Princess Eugenie of York and her husband Jack Brooksbank leave in a carriage after their wedding ceremony at Windsor Castle, Windsor, Britain REUTERS Princess Eugenie marries Jack Brooksbank - in pictures Sarah, Duchess of York and Princess Beatrice of York and the bridesmaids and page boys, including Princess Charlotte and Prince George, wave off Princess Eugenie of York and Mr. Jack Brooksbank following their wedding at St. George's Chapel on October 12, 2018 in Windsor, England. Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Newlyweds Princess Eugenie of York and Mr. Jack Brooksbank wave to the crowds from their carriage after their Royal wedding at St. George's Chapel on October 12, 2018 in Windsor, England. Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Britain's Princess Eugenie of York and her husband Jack Brooksbank leave in a carriage after their wedding ceremony at Windsor Castle, Windsor, Britain Reuters Princess Eugenie marries Jack Brooksbank - in pictures Jack Brooksbank and Princess Eugenie of York in a carriage after their wedding at St George's Chapel in Windsor Castle, Windsor, Britain Reuters Princess Eugenie marries Jack Brooksbank - in pictures Britain's Princess Eugenie and her husband Jack Brooksbank (unseen) ride in a horse-drawn carriage after their royal wedding ceremony in St George's Chapel at Windsor Castle, in Windsor, Britain EPA Princess Eugenie marries Jack Brooksbank - in pictures An onlooker is seen watching from a window of a building inside Windsor Castle AFP/Getty Images Princess Eugenie marries Jack Brooksbank - in pictures Princess Eugenie of York reacts as she and and her husband Jack Brooksbank walk to an Aston Martin DB10 as they leave Windsor Castle AFP/Getty Princess Eugenie marries Jack Brooksbank - in pictures Jack Brooksbank and Princess Beatrice help Princess Eugenie in her car as she leaves Windsor Castle after her wedding for an evening reception at Royal Lodge PA

Thames Valley Police said it could not estimate the cost of its operation until after the wedding, but it is reportedly expected to be about £2m.

The force picked up a bill of between £2m and £4m when Prince Harry and Meghan Markle wed in Windsor in May.

Republic urged the royal family to “step forward and pay up” the full cost of Eugenie’s wedding. It said the ceremony should be treated as a private event because the princess is not a working royal who carries out public duties.

“There is a strong feeling, even among monarchists, that we shouldn’t be paying for Eugenie’s big day,” a Republic spokesman said.

“Most Brits opposed taxpayer funding of Prince Harry’s wedding but as with all royal events were forced to accept it. But there’s something different about Friday’s royal wedding, and people aren’t happy.

“The monarchy is stretching its public support to breaking point. There’s a real risk Friday’s wedding will damage the royals for a long time to come.”

He added: “There is still time for the royals to step forward and pay up. It’s without question the right thing to do.”

More than 46,500 people have signed Republic’s petition calling for “no public funds” to be spent on the wedding.

Buckingham Palace declined to comment.

The Metropolitan Police spent £6.35m on policing Prince William’s wedding to Kate Middleton in 2011.