A man has admitted damaging a painting worth £1.7m with a hammer at the National Portrait Gallery.
The gallery said the painting will be repaired
Mark Paton, 44, offered no explanation as to why he repeatedly hit the 18th Century oil painting of Samuel Johnson by Sir Joshua Reynolds.
Gallery staff found the hammer in the portrait and Paton next to it, City of Westminster Magistrates' Court heard.
District Judge Quentin Purdy ordered psychiatric tests on Paton, who caused £10,000 damage.
Paton, who lives in a shelter in Redbridge, east London, pleaded guilty to causing criminal damage and possession of a hammer with intent to cause criminal damage.
Euan MacMillan, defending, said: "He has nothing against Sir Joshua Reynolds or Samuel Johnson, the subject of the painting.
"I am not in a position to elaborate on this offence although Mr Paton says he will tell me at some stage."
The court heard Paton bought the hammer and managed to sneak it in past the security before attacking the canvas on Wednesday afternoon.
The judge said: "It seems to me to be a premeditated attack. He purchased the hammer and did the damage.
"I'm mindful - given the absence of any explanation - to ask the court's psychiatric team to make any observations."
Paton was remanded in custody until 14 August and he will be sentenced after the reports of the psychiatric tests come in.
The painting, said by the gallery to be one of its most popular, is part of the permanent collection on the top floor and will be repaired.