Lawyers representing a young mum, serving a life sentence for her part in a horrific murder, are appealing for help to trace three witnesses they believe could provide evidence to overturn her case.

Laura Mitchell, of Buttershaw, Bradford, was 22 when she was convicted, along with her boyfriend Michael Hall, and Henry Ballantyne, of murder and violent disorder, after dad-of-two Andrew Ayres was beaten and kicked to death in a row over a taxi.

Carl Holmes, who inflicted the fatal injuries by stamping on Mr Ayres’ head, pleaded guilty to the murder.

All four were jailed for life and told they would have to serve at least 13 and a half years before they could be considered for parole.

The murder took place on the car park of the King’s Head pub in Halifax Road, Buttershaw, during the early hours in January 2007. Mr Ayres, 50, died from head injuries. His face was said to be unrecognisable following the attack.

A mace, knuckleduster and CS spray were used during the gang attack, and the trial judge described it as a “brutal, intense and vicious attack”.

Mitchell, now 28, has had a failed appeal against her conviction, her lawyers claiming she had played no part in the savage attack on Mr Ayres and had no inkling he might be killed.

But the Appeal Court judge, Lord Justice Thomas, ruled she had started the trouble that led to Mr Ayres’ death and the jury was entitled to find the murder was a joint enterprise between Mitchell and a group of friends who acted like “absolute animals”.

Now lawyers representing Mitchell, who is serving her sentence in a women’s prison in the Midlands, have made a public appeal for help to contact three women witnesses – they are named as Elaine Doherty, Claire Rothery and Sheila Cooney – who the lawyers believe may have important evidence.

Derek Buxton, of Henry’s Solicitors, in Stockport, Greater Manchester, said he had recently seen Mitchell in prison.

He said: “After serving six years, she remains absolutely adamant that she is innocent of murder. She says that while the attack was happening she shouted ‘stop all this’ to the men.

“She says that two of the women witnesses were in a car and must have heard her say this. The third woman gave evidence of identity and Laura believes she made an honest mistake in identifying her at the scene of the murder and may now feel she would be in trouble if she admitted the mistake, which she would not.

“I would ask these witnesses, or anybody else who may have further information which could help, to contact us.

“If what Laura says is correct, and the witnesses corroborate it, it would be an insecure conviction which would mean we could go back to the Royal Courts of Justice for a review and to set a date for a hearing which could overturn her conviction.

“The joint enterprise link is very tentative and this should be looked at in the interests of justice. She does not dispute being there, but she disputes that she became involved in the fracas.”

Mr Buxton has asked anyone who can help to contact him on (0161) 477 8558, or 07912 357757.