The Tower Of London has been closed after an incident near the display case containing the Crown Jewels.
Four people have been arrested on suspicion of causing criminal damage.
It is understood that food was throw at the display cases containing the Jewels.
The popular tourist destination in Central London has been closed to allow police to preserve the scene for investigation work to take place.
A Metropolitan Police spokesperson said: “Police were called at 09:48hrs on Saturday, 6 December to the Tower of London following reports of criminal damage to a display case, containing the State Crown.
“It was reported that four protesters threw suspected food onto the case before two left the scene.
“Officers worked closely with City of London Police and security officers and four people have been arrested on suspicion of criminal damage. They have taken into custody.
“The Tower has been closed to the public while the police investigation continues.”
