LONG-term domestic abuse should be a new category of crime rather than being treated as a series of individual assaults, campaigners have warned, after former MSP Bill Walker was jailed for 12 months.

Walker received the maximum sentence possible yesterday at Edinburgh Sheriff Court for offences against three former wives and a stepdaughter spanning three decades.

Lily Greenan of Scottish Women's Aid said the organisation would press the Scottish ­Government and Crown Office for a new approach, including new legislation.

She said: "Despite great efforts by the police and the Crown Office to develop more effective responses to domestic abuse, our current court response is limited by the focus on 'incidents' of assault.

"If someone commits a single act of 'common assault', summary court is absolutely appropriate. However, if they commit that same act of assault repeatedly, against a partner or several partners for years, we believe that's a different kind of crime, with a significantly greater impact, and it should be prosecuted in a higher level court with a greater range of sentencing powers."

She was backed by Professor Evan Stark, founder of one of the first refuges for women in the US, who is currently a Leverhulme exchange fellow at Edinburgh University. The author of Coercive Control: How Men Entrap Women in Personal Life agreed that a new law was required to treat long-term patterns of behaviour - which he likens to hostage-taking - as ­serious crime.

Sheriff Kathrine Mackie said Walker, 71, showed contempt for his victims, adding: "I have been unable to detect, either during the trial or in the reports, any evidence of remorse for anything or anyone except yourself.

"You maintain your denial of any wrongdoing, and that you perceive yourself as the victim of various conspiracies, among your former wives, political opponents and the media.

"Your incredulity at being convicted of these offences and your perceived victimisation are further indications of your ­abdication of responsibility for your behaviour.

"Your denial appears to me to be absolute. There is no acknowledgement of any unacceptable behaviour. There is no indication of any motivation to change."

Walker, who clung on to his Dunfermline seat for 16 days after being convicted, plans to appeal his conviction and will go to the High Court seeking interim liberation from custody.

Sheriff Mackie found Walker guilty of assaulting his first wife Maureen Traquair on three ­separate occasions in the 1960s and 1980s, giving her a black eye two weeks before they married in January 1967.

He assaulted his second wife, Anne Gruber, 15 times between 1978 and 1984. Mrs Gruber was punched, slapped, kicked and pushed to the ground. Walker also breached the peace by leaping into her home brandishing an air rifle.

Walker, of Alloa in Clackmannanshire, was also found guilty of assaulting and injuring Mrs Gruber's 16-year-old daughter, Anne Louise Paterson, by ­repeatedly striking her on the head with a saucepan in 1978.

Walker was found guilty of four assaults on his third wife Diana Walker, three of which involved slapping or punching her on the face between June 1988 and ­January 1995.

The former SNP MSP, who was suspended and later expelled from the party after the allegations surfaced in March last year, claimed his ex-wives colluded against him.

Diana Walker said it was hard to forget the abuse. She said: "I don't really have any feeling in relation or anything like that, I feel quite sad at times that it's had to come to this.

"I was frightened of him, and I'm frightened that when he gets out there might be some repercussions."