The twins are well known for their violent reign in the ganglands of east London in the 1950s and 1960s, but the sale by Mander Auctioneers contains many items that throw a different light on their characters.

Among the lots is a musical jewellery box, decorated by the brothers during their incarceration and presented to a good friend as a present, together with an accompanying letter from the twins.

The sale also includes Christmas cards sent from Ronnie and Reggie to the same friend during their years in prison – 30 to 40 letters written by the pair on their own headed paper– and a signed first-edition copy of Reggie's 1991 autobiography, Born Fighter.

Everything being auctioned stemmed from the son – who lives near Wisbech – of the man they were originally given to as presents by the Krays, although he wishes to remain anonymous.

Auctioneer James Mander said: "There are some photos of the Krays with him, which he took probably in the early 1950s because they look very young.

"It's quite nice because it's very personal. He was obviously very good friends with them."

The uniqueness of the jewellery box cottage has made it difficult to value for the sale, said Mr Mander, who has estimated its price at between £100 and £200.

He said: "I don't know how I'm supposed to value that. It's a real guess."

The sale starts at the Church Street auctioneers at 11am.