A woman has been arrested after she allegedly tried to climb the front gates of Buckingham Palace.
The woman, who is in her 30s' was apprehended by police officers before she was able to access the palace grounds, Sky News reports.
Eyewitnesses reported seeing a woman being physically restrained on the fence outside the palace by two officers as a crowd of tourists looked on.
She was handcuffed and bundled into an awaiting police car.
A statement by the Metropolitan Police said: "At 5.40pm on Saturday, officers in the area of Buckingham Palace observed a woman climbing the front gates of the palace.
"She was arrested on suspicion of trespass under Section 128 of the Serious Organised Crime and Police Act 2005, trespass on a designated site and is currently in custody at a central London police station."
The incident is not believed to be terror-related. The attempted security breach follows two earlier incidents in London today (7 October) which sparked alarm in the capital.
In South Kensington a man ploughed a car into crowds outside the Natural History Museum on Exhibition Road in London.
The Metropolitan Police have detained a suspect who was driving the vehicle and confirmed that it is a road traffic investigation and not a terrorist-related incident. Police have yet to determine the assailant's motives but are "keeping an open mind".
Earlier this evening Euston station was evacuated following a security alert, however police later confirmed there was "nothing suspicious" to report.