A collection of more than 200 letters written by one of the UK's most notorious gangsters is expected to fetch about £15,000 at auction.

The 215 letters written by Reggie Kray between 1988 and 1991 during his imprisonment in HMP Maidstone detail conversations between the gangster and his ghostwriter Carol Clerk as they worked on his autobiography Born Fighter.

Notes could not be taken during prison visits, so the gangster wrote down his thoughts and posted them after meetings.

The letters are said to contain "bizarre ideas and storylines" for the autobiography and will be sold at McTear's auctioneers in Glasgow on June 2.

In the book, published in 1990, Kray tells how he and identical twin brother Ronnie created their infamous crime empire in the East End of London through violence and intimidation in the 1950s and 60s.

They were both jailed for life in 1969 for the murders of fellow gangsters George Cornell and Jack ''The Hat'' McVitie.

Ronnie died of a heart attack in prison in 1995 while Reggie died of terminal cancer five years later, just weeks after he was granted compassionate release from prison because of his illness.

The collection of letters, which also includes a signed copy of Born Fighter, is valued between £10,000 and £15,000.

Dozens of the Krays' belongings have previously been sold at auctions across the UK.

In 2013, two oil paintings of the Norfolk landscape by Reggie during his stay in Wayland Prison were sold for £1,200 while Ronnie's black-rimmed glasses and a decommissioned gun used by the twins have also been sold to collectors.

McTear's managing director Brian Clements said: "Ronnie and Reggie Kray's names are synonymous with gangland life in the East End of London in the 60s and anything associated with the pair always attracts interest.

"We do see Kray items coming to auction but we have never seen anything on this scale going under the hammer.

"The fact that all the letters relate to one particular area makes the collection unique and of particular interest to collectors.

"When Reggie met his ghostwriter in prison they were not allowed to take notes, so all Reggie's thoughts and ideas had to be put in the form of letters after the meetings.

"The collection shows that he was a prolific letter-writer, often penning three or four a day, with some even written on Christmas Day."