Speaking to ITV News, Vladimir Umanets, insisted he was not a vandal and felt he had been "completely attacked" over the writing daubed on the Rothko mural. He defended "Yellowism" which he founded, and said the police hadn't contacted him - yet.
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The operation to recover the unexploded bomb near the Houses of Parliament let to disruption in central London overnight.
Southern parts of England and Wales will see sunny skies after a frosty start.
A police spokesman said the incident in the Bourke Street Mall on Friday was not related to terrorism.