The son of Georgina “Sally” Challen has shared a picture of his mother on her first day of freedom since she was convicted of murdering her husband in a hammer attack in 2010.

Her sons James, 35, and David, 33, have campaigned for their mother’s release on the grounds that their father subjected her to decades of coercive and controlling behaviour and abuse in their 31-year marriage.

In her 2011 trial Challen, 65, of Claygate, Surrey, admitted killing her husband, Richard, in August 2010 but pleaded not guilty to murder. After a seven-day trial she was found guilty and sentenced to 22 years in prison.

In March last year she won leave to appeal against her conviction on the grounds that she had endured coercive and controlling behaviour from her husband – a form of domestic abuse not recognised in law until 2015, four years after her trial, when it was written into statute books under section 76 of the Serious Crime Act.

In February this year her conviction was quashed at the court of appeal with a retrial ordered after new evidence came to light about her state of mind at the time of the killing.

On Friday Challen appeared at the Old Bailey via video link from HMP Bronzefield in Ashford, Surrey, and was granted conditional bail after entering a plea of “not guilty, but guilty to manslaughter”.

Mr Justice Edis set a date for a further hearing on 7 June and a trial on 1 July “if necessary”.

Tweeting the family picture on Saturday David, who has been campaigning vocally for his mother to be freed, captioned the photo “first day home with our mother after 9 years in prison”.

The brothers told the Daily Telegraph: “We have never entertained the thought of our mother being released before now, every moment we now spend with her is so precious and we look forward to all of it.”