IT was a fatal blunder that summed up his hypocrisy and enraged his former wives.

In February 2011, Fife councillor Bill Walker made a public visit to a Dunfermline charity for "abused men". He posed for photographs and spoke up for the "victims of this type of domestic trauma", which he said involved children being used as "pawns".

Twelve months later, Walker returned to the same theme as the town's newly-elected Nationalist MSP. He welcomed a £400,000 grant to Fife Women's Aid and said the cash was vital for "aiding abused women".

Walker was using his position as an elected representative to pose as a champion of domestic abuse victims.

The reality was that he was responsible for a 30-year catalogue of violence against a former step-daughter and a trio of ex-wives, two of whom were now angry enough to expose his double standards. The beatings were also recorded on paper, as many of the kicks, slaps and punches that wrecked Walker's three marriages were laid bare in court documents and the National Archives.

When the Sunday Herald unmasked Walker last year, the SNP suspended him within hours and expulsion from the party followed.

An investigation by Fife Constabulary led to 23 separate charges of assault, one charge of breach of the peace, and a trial that gave his victims a chance to have their voices heard.

Maureen Traquair, now in her 70s, married Walker in 1967 and was the first to give evidence at Edinburgh Sheriff Court.

She told of how Walker gave her a black eye before their wedding day, an attack that led to her wearing green make-up to cover the bruising. Traquair also alleged that he "hit me on the face" after she confronted him about another woman.

Anne Gruber was the next former spouse to take the stand. She and Walker wed in 1970 and they lived together in Edinburgh and Midlothian.

They had children, but Gruber's life was nearly ruined by Walker's violence. She told the court of how he kicked and punched her, knocked her to the ground and threatened to throw coffee on her face.

Gruber also said he spat on her and pulled her hair over the course of their troubled 16-year marriage. Sexual assault was not one of the charges, but Gruber told the court that Walker raped her: "I was being absolutely bullied. He was seeing other women. I was being raped more regularly."

Diana Walker, a teacher, was the third ex-wife to be a called as a prosecution witness. Between their marriage in 1988 and divorce a decade later, she said the MSP repeatedly lifted his hands to her.

However, her court evidence was only a small part of her story. She told this newspaper last year how Walker "went berserk" in a San Diego hotel room in 1989.

For no apparent reason, she said he started "punching me, kicking me, hitting me", before beating her with a metal coathanger.

He put her through a similar ordeal in Corsica, where she said Walker "completely flipped", tore off her clothes and punched her. However, due to these alleged incidents taking place outside Scotland, no charges could be laid.

The court also heard unflattering evidence of a non-violent nature: Walker had been with another woman on the night Gruber gave birth to his child; he taped his third wife's phone calls; and he threw a gold watch given to him by Traquair into a furnace.

Diana Walker even explained how he drew up a formal agreement laying out her marital responsibilities: "It stated that I would pay the utility bills, that I would do the grocery shopping and the cleaning. I was also supposed to do the washing, ironing and chores."

If Walker was a repellent husband, he was also an appalling parent. Gruber told the court how Walker hit his teenage step-daughter on the head with a saucepan during a row: "He battered her so hard she was down on the floor. Her head was bleeding and she was bruised."

A decades-old court battle had already established Walker as a callous and uncaring father. In 1990, Lord Clyde slammed Walker's "concealment of the truth" about his income during an alimony dispute.

The judge said Walker's "deception" had exposed him to "proceedings of a criminal nature".

In a child access case, his former step-daughter, Louise, said in an affidavit that Walker took "great enjoyment" in "reprimanding" her: "Rather than the usual parental smack, discipline was regarded by Mr Walker as almost a ritual, by which he could display his authority over us. He would send me upstairs to wait, possibly 20 minutes, and then insisted on smacking me repeatedly on my bare bottom."

She said these smacks continued until she was 15 years old. Louise added that he was a "cruel, insensitive and dangerous man", who was "wholly unsuited to being either a father or step-father".

Walker's son, Douglas, last year described him as a "bastard of the highest order".

In Edinburgh Sheriff Court, Walker's defence did not hold up to scrutiny. He cited self-defence for the attack on his former step-daughter - but the idea of a 6ft 2in male being under attack from nervy teenager did not add up.

He had also claimed Gruber and Diana Walker had co-­ordinated their allegations, but the pair were not friends.

His worst moment came when his fourth and current wife, who was supposed to be his star defence witness, confirmed that she too had called the police after a fight. She said: "He pushed me and I was so incensed that I went outside and I was beside myself with rage, 'No-one's treating me like that'.

"I got into my car and went down to the police station and said there had been an incident."

Sheriff Kathrine Mackie's verdict was unsurprising. Mackie - who jailed Labour peer Lord Watson for wilful fire-­raising in 2005 - said she "did not find the accused to be a credible witness" and found Walker guilty of all charges. By contrast, she said she believed that the MSP's three former wives were "credible and reliable".

Walker's reckoning has produced a rare political consensus at Holyrood. First Minister Alex Salmond, as well as opposition leaders Johann Lamont, Willie Rennie, Ruth Davidson and Patrick Harvie, have called on Walker to quit Holyrood.

Given that the sheriff cannot impose a large enough sentence to trigger his disqualification automatically, Walker's resignation can only come from him.

His ex-wife Diana told the Sunday Herald last year that Walker was "money mad" and would be unlikely to do the honourable thing.

If Walker stays on until April 2016 - the scheduled date of the next Holyrood election - he will pocket around £155,000 in salary and a £29,000 resettlement grant.

He will also benefit from taxpayer-funded pension contributions and the full suite of travel and accommodation expenses enjoyed by MSPs.

Walker would not even need to show up at Holyrood to benefit from these payments. He could move to Mallorca and the Parliament could do nothing about it.

Thursday's verdict was closure for the three wives he abused, but also marked the beginning of a rocky period for Holyrood.