Art restorer Amy Griffin, from the Simon Gillespie Conservation Studio, says that it should be possible to remove the graffiti without damaging the original painting.
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After his arrest, Apopei described his girlfriend as "a witch" and paced around his cell ranting about devil worship.
Controversial police chief Cressida Dick was today named Scotland Yard's first woman Commissioner.
Police accidentally sent letters to seven people killed in the Croydon tram crash, inviting them to a survivors meeting.