A letter written by the last woman to be hanged in Great Britain just before she died says her solicitor can reveal “the truth”.

Nightclub hostess Ruth Ellis, from Rhyl, Denbighshire, was executed on 13 July 1955 after being convicted of murdering her lover David Blakely.

The day before this, she wrote to George Rogers, the Labour MP for Kensington North who campaigned for her to be pardoned, and appears resigned to her fate, saying she is “quite well”.

“I gather you will speak to Mr Victor Mishcon, and then you will find out the truth,” she wrote in the letter, which will be auctioned next week.

The letter is written on prison paper with her name, prisoner number and the date at the top.

Forum Auctions in London estimates it will sell for between £1,500 and £2,000.

“This poignant letter, written the day before her execution, hints at Ellis’ divulging to her lawyer Victor Mishcon that she had been given the gun which she used to kill her lover David Blakely by Desmond Cussen, who had also showed her how to use it,” said Rupert Powell, deputy chairman at the auction house.

“It is almost certainly one of the last letters she ever wrote.”

Mr Rogers visited Ellis in prison and received her agreement to an appeal to the Home Secretary for clemency – or leniency.

However, this was denied, the auction house said.

Ellis was hanged at London’s Holloway Prison.

She shot Blakely outside The Magdala pub in Hampstead, London, following a tumultuous relationship involving infidelity on both sides.

She had an abortion, which was illegal in the UK at the time, and was physically abused by the racing driver who punched her in the stomach during an argument, leading to a miscarriage.

In the letter, Ellis thanks Mr Rogers for offering to take her son on holiday, and expresses her gratitude for his efforts to help her.

“I understand you so kindly offered to take my son Clare Andria, away for a holiday…I will take this chance, of thanking you, once again, for the help you offered me,” she writes.

She signs off with a final “goodbye”.

The British public was already questioning whether capital punishment had a place in 20th Century and, two years after Ellis’ hanging, legal changes saw diminished responsibility introduced as a defence.

Ellis’ grandchildren are now seeking a posthumous pardon, saying she was physically and emotionally abused by her partner before she killed him.