A man has defaced a portrait of the Queen with paint at London's Westminster Abbey, with a campaign group for fathers' rights saying he was one of its members making a "desperate" plea to the monarch for help.
The painting of the 87-year-old monarch, "The Coronation Theatre: Portrait of Her Majesty Queen Elizabeth II" by London-based artist Ralph Heimans, had been part of a display marking the 60 years since the queen's coronation in 1953.
"In an incident at lunchtime today, a visitor to the Abbey sprayed paint on the Ralph Heimans portrait of the queen presently on display in the Chapter House," an Abbey spokesman said.
"Until work can be done to remedy the damage, it will, very regrettably, not be possible to have the painting on public view."
London's Metropolitan Police said security guards had detained a suspect at the scene. Officers arrested the 41-year-old man on suspicion of criminal damage and he has been taken to a central London police station for questioning.
Fathers4Justice (F4J), a group which supports divorced fathers seeking greater access to their children, said one of its members had carried out the attack to bring attention to his plight ahead of Father's Day on Sunday.
"We understand that a desperate father belonging to Fathers4Justice has attempted to write the word 'help' on a portrait of the queen in Westminster Abbey," the group said in a statement, adding it was not directly involved.
F4J named the man as Tim Haries from Doncaster in northern England. "Tim Haries has lost all contact with his children and felt he had nothing to lose by appealing directly to the queen for help by spraying his plea onto her portrait," said Campaign Director Jolly Stanesby.
F4J gained notoriety in 2004 when a campaigner dressed as Batman climbed the queen's Buckingham Palace residence and another threw purple flour bombs at former Prime Minister Tony Blair while he addressed parliament.
In 2006, two of its members were arrested after scaling London's Westminster Abbey with a crucified dummy Jesus Christ. Earlier that year, the campaign group said it had decided to disband after reports that police had foiled a plot to kidnap Blair's five-year-old son Leo.
A new official campaign group reformed some years later.
Last week, the queen and senior members of the royal family attended a service of celebration at the Abbey to mark the diamond anniversary of her coronation.