Video report by Lewis Vaughan Jones
A protester is being held by police on suspicion of defacing a portrait of the Queen in Westminster Abbey.
The man, believed to be a Fathers4Justice activist, is said to have attempted to write the word "help" in spray paint over the Ralph Heimans canvas, which was put on public display just last month.
The oil painting, entitled The Coronation Theatre, Westminster Abbey: A Portrait of Her Majesty Queen Elizabeth II, has since been taken from public display as a result of the damage.
Fathers4Justice named the suspect as father-of-two Tim Haries from Doncaster, a "desperate dad" wanting to draw attention to the issue of shared parenting.
Officers were called to the Abbey around 12.30pm today after security guards detained a 41-year-old man.
He was arrested on suspicion of criminal damage and taken to a central London police station where he remains in custody, a Metropolitan Police spokesman said.