Jonty Bravery, 20, was arrested after his alleged victim, in his 30s, told another inmate and prison officials were informed, a source told the Mirror.
Bravery was 17 when he hurled a French tourist from the Tate’s 10th-floor viewing platform in central London.
He was given a life sentence with a minimum 15 years for the crime which took place in August 2019 .
Bravery was arrested on suspicion of rape at at Belmarsh Prison where he is an inmate.
He told police he had planned the art gallery attack to prove he had a mental illness.
Bravery also said he wanted to “be on the news”. His victim suffered life changing injuries.
The Metropolitan Police said on the rape allegation: “A man in his 20s was arrested on suspicion of rape and taken to a South London police station. He was released on bail back into the custody of the prison. Enquiries are ongoing.”
A Prison Service spokesman said: “We are working closely with the police investigation.
Meanwhile the victim of the Tate Gallery incident who was on holiday with his parents from France has faced multiple operations after horrific injuries sustained in the fall.
He has gone back to school and has learned to ride a tricycle, his family have revealed in a letter outlining his progress in May.
It read: “Our little knight has come back to school. Two mornings a week.
“He needs to make new friends of course but he is very sociable, and the children in this school are very welcoming, as well as the school teacher and other professionals.
The letter was posted on a GoFundMe page appealing for funds to cover his medical costs.
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