Detectives are asking anyone who recognises a woman shown on hospital CCTV footage to call Surrey Police on 101, quoting the reference RM/13/4481 or call Crimestoppers anonymously on 0800 555 111.
Police want to speak to her in connection with a number of thefts from elderly and vulnerable patients.
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The prison was originally opened in 1852 as a mixed prison before becoming the first female-only local prison in England in 1902.
The victim was travelling between Seven Sisters and Highbury and Islington when she was assaulted.