Police are hunting for a vandal who walked into the Tate Modern art gallery and defaced a valuable painting by Mark Rothko.
The visitor daubed black paint on "Black on Maroon" during a visit to the gallery yesterday afternoon.
Eyewitness Tim Wright posted on Twitter:
"This guy calmly walked up, took out a marker pen and tagged it. Surreal. We gave a description to the gallery. Very bizarre, he sat there for a while then just went for it and made a quick exit."
Earlier this year, Rothko's Orange, red, yellow was sold for £53.8 million - the highest price ever paid for a piece of post-war art at auction.
The 1961 painting went under the hammer at Christie's in New York.
More top news
Pregnant woman who was labour has had her "phone snatched while calling for and ambulance to hospital".
It will be increasingly cloudy this evening, with sporadic outbreaks of rain or drizzle spreading in during the first half of the night.
A derelict north London garage has gone on sale for £360,000 - more than the cost of a flat on the same road.