Muriel Jakubait believes her sister Ruth Ellis did not know what she was doing

Muriel Jakubait, who is now 77 years old, says the true facts did not emerge at her younger sister's trial. The jury took only 23 minutes to convict her of murder.

She has been Inspired by the recent case of Derek Bentley, who was hanged for his part in the murder of a policeman. The conviction was recently quashed.

Miss Ellis, 29, was executed in 1955 at Holloway Prison, north London, for shooting dead her lover, racing driver David Blakely.

Solicitor Bernard de Maid says the last woman to be hanged in Britain should never have been put to death because vital evidence was withheld and the killing was "a true crime of passion".

Solicitor Bernard de Maid explains why Ruth Ellis should not have been hanged

Mr de Maid told the BBC that the they were not disputing the fact that Miss Ellis killed Blakely, but that she was unable to plead to a lesser crime.

Had she been given the chance to plead guilty to manslaughter and the details of provocation had emerged, she may have been given a short sentence or probation, he said.

Ruth Ellis shot her lover David Blakely outside a north London pub

"It was a true crime of passion - the familiar eternal triangle where she shot and killed her then current boyfriend at the behest of a new, incoming older boyfriend.

"She was ditched, she was physically abused and she took her revenge."

Dying wish

Mr de Maid said Ellis's new boyfriend supplied her with a gun, showed her how to use it and then drove her to the scene of the crime, after provoking her into carrying out the killing.

In court she ordered her then solicitor not to reveal any of those details so as not to involve the other man.

"He emigrated pretty quickly after the trial to Australia where he has since died," said Mr de Maid, adding that this was part of the reason why Ellis's sister now wanted to have the case reopened.

It is due to go before the Criminal Cases Review Commission, a body recently set up to investigate miscarriages of justice.

It will decide whether or not the matter will be referred back to the Court of Appeal.

Mr de Maid said: "I'm quite confident they will find in our favour."

Mrs Jakubait says she does not expect a pardon, but stressed that it was her "dying wish" to see her sister's conviction reduced to manslaughter.

The case of Ruth Ellis became famous, with her story becoming the subject of several books and the film, Dance with a Stranger.