David Litvinoff

https://en.wikipedia.org/wiki/David_Litvinoff

David Litvinoff (sometimes Litvinov; born David Levy; 3 February 1928 – 8 April 1975)[1] was a consultant for the British film industry who traded on his knowledge of the low life of the East End of London. A man for whom there are few truly reliable facts, it is unclear how genuine his expertise really was, though he certainly knew the Kray Twins and was particularly friendly with Ronnie Kray, according to a biography published in 2016.[2] He entertained his showbiz friends with stories of the Krays' activities[3] and his niece Vida described him as "the court jester to the rich, smart Chelsea set of the sixties"