Robert McCartney’s partner and sisters campaigned for three and a half years to bring his killers to justice, winning the support of President Bush, Senators Edward Kennedy, Hillary Clinton and John McCain, and 600 Members of the European Parliament.

Yesterday their campaign was defeated by an even more powerful one — that of street-level intimidation and a wall of silence enforced by the Republican hard men who still rule Northern Ireland’s working-class nationalist communities through terror.

“It’s a victory for the IRA,” Catherine McCartney told The Times, with evident bitterness.

Judge John Gillen acknowledged that the family would be “frustrated and disappointed” by the verdict. That was an understatement. The women have sacrificed homes, careers and mental wellbeing in their pursuit of justice. They have been abandoned by friends and made pariahs in their own communities.

They start each day knowing they could encounter in Belfast’s streets or shops not only the three men acquitted yesterday, but at least a dozen others they believe to have been involved in or linked to Mr McCartney’s murder and subsequent cover-up.

Ms McCartney, 40, said: “I am sure they’ll be having a party tonight at Magennis’s [the bar where McCartney was stabbed].” Seeing them in the street was “like an out-of-body experience”, she said. “What do you do? Walk on by? Say something? You don’t go about the city because you’re going to run into them. Our freedom has been taken away.”

The senior IRA man she believes ordered the murder is now on the government payroll, she says. Before the verdict Ms McCartney had told The Times that she and two sisters were thinking of emigrating if the defendants were convicted. Last night she vowed to fight on, but acknowledged a yearning to leave Northern Ireland: “If I had a plane ticket I would go today.”

Mr McCartney was murdered in January 2005. Within days the sisters had begun their campaign. Intelligent, articulate and determined, Belfast’s “Famous Five” and Bridgeen Hagans, mother of his two sons, appealed for witnesses and challenged the old “code of honour” that prevents nationalists from going to the police.

They refused to be silenced by threats to burn down their homes, by pickets, missiles or letters full of obscenities and excrement. They held a candlelit vigil, addressed rallies and, although they had in the past voted for Sinn Fein, gave interviews in which they portrayed the IRA as oppressors, not protectors, of nationalist communities.

They met Tony Blair and Bertie Ahern, the British and Irish prime ministers. They went to Brussels where 600 MEPs signed a motion condemning IRA “violence and criminality”. In Washington Mr Bush pointedly welcomed them while excluding Sinn Fein leaders from St Patrick’s Day celebrations at the White House.

Their campaign came at a critical stage of the peace process, when Sinn Fein’s admission to a power-sharing Stormont government hung in the balance. The party’s leadership temporarily suspended several members. It issued weasel-worded statements deploring the killing and urging witnesses to go to the family, or a solicitor — but not to the police.

The IRA squirmed. It claimed to have expelled three culprits. It offered to “shoot” those responsible. Finally, half a year after McCartney’s murder and the IRA’s £26 million Northern Bank robbery, it announced it was ending its 35-year-old armed struggle.

Catherine McCartney has no doubt that the campaign helped to precipitate that historic announcement. “I think [the Republicans] realised their time of riding two horses was up,” she said. But the sisters could not break down the IRA-imposed wall of silence protecting their brother’s killers.

More than 60 people were in Magennis’s bar the night Mr McCartney was fatally stabbed, but most claimed to have been in the toilet at the time. Belfast’s black-humourists dubbed that bathroom “The Tardis” after Doctor Who’s tiny telephone box with its voluminous interior.

Some witnesses retracted or changed their statements after “visits” from IRA godfathers. The bar’s closed-circuit television footage was destroyed. Passing drivers had seen the fight spilling on to the pavement, yet just one independent witness — a woman driver waiting at traffic lights near the bar — had the courage to testify in the trial. Judge Gillen said that while “Witness C” was “transparently honest” she could have been mistaken about what she saw.

“I believe the IRA had a big hand in obstructing justice,” Ms McCartney told The Times. “Sinn Fein has not co-operated not one iota,” despite its declarations of support for the Police Service of Northern Ireland which replaced the RUC in 2001.

The six women have paid a high price for daring to challenge the IRA. Ms Hagans was forced to leave her home in Short Strand, a Roman Catholic enclave in predominantly Protestant East Belfast. So was Paula McCartney, 43, the last of five generations of her family to live in Short Strand. “She felt she could no longer go round to the shop. She didn’t feel she could function in the place any more,” Catherine McCartney said. Paula is now thinking of leaving the country.

Gemma, 44, a nurse, suffered from depression and took a year off work. Later she was manning a cervical cancer testing unit in the Markets area of Belfast, close to the murder scene, when a man associated with Mr McCartney’s killers recognised her, spat at her and ordered her to leave.

Donna, 42, ran a sandwich shop in Belfast. She struggled to keep it going, then gave up. She too was suffering from depression. “She didn’t want to interact with anyone outside the family,” said Catherine, who added that Donna would leave Northern Ireland if the opportunity arose.

Claire, 30, suffered a miscarriage eight months after her brother’s murder. Her partner left her, she had to move out of their North Belfast house and she too suffered from depression. Last Christmas she encountered Terry Davison, one of the defendants cleared yesterday, in a Belfast shop and told him what she thought of him. Catherine said: “She was shaking afterwards.” Catherine, 40, had moved to a small town 30 miles from Belfast shortly before her brother’s murder. She had to return when the campaign took off, and gave up her teaching job. She is now unable to find work. Being such a controversial figure has not helped, she says, and she recently visited Australia with a view to emigrating.

Catherine said she has yet to hang up her brother’s picture in her house, or visit his grave, or find time to grieve for him. She said she would now take a few days to consider what to do next. She feels she should fight on, hoping new witnesses will come forward, but also accepts the need to be realistic.

The political climate was no longer helpful, she said. The campaign had become an embarrassment at a time when politicians had a vested interest in not rocking the Stormont boat, in pretending the Republicans had renounced violence for good. “Everyone seems to be in on it. They all turn a blind eye when it suits.”

It was, she said, deeply frustrating to watch Republicans “harping on about justice and equality and the need for effective policing when you know they played a major role in obstructing a murder investigation”.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• Foxy Knoxy snared by her lust and her lies
• Britain is the land of the shrinking family
• Zac Goldsmith: Not such a green god