The Public Guardian of British Columbia is suing the federal government on behalf of three children who watched a prisoner slash their mother's throat at a Christmas party.

The B.C. Supreme Court lawsuit asking for compensation claims the boys, all under 11, were with their mother at the Kent Institution in the Fraser Valley when she was attacked in December 2003.

Jennifer Lutz married Earl Nantais in a prison wedding just four months before he stabbed and slashed her 28 times.

She survived the attack, but was left with significant scarring, both physically and emotionally.

The lawsuit claims all three boys tried to stop the attack.

In the reasons for convicting Nantais of attempted murder, the judge in the case noted the couple were sitting on a bench outside the party when the attack began, apparently unprovoked. The boys were nearby.

The attack was seen by a guard in the watch tower, but it was several minutes before guards could respond.

Nantais and Lutz had known one another years before and reconnected when she visited the prison.

Court documents say Nantais had a history of violence toward women and prison management should have known he was a high risk to commit another violent act.

"At all material times the defendant was aware that, whilst in prison, Nantais had been caught with knives in his cell," the lawsuit states.

The court documents say prison officials were negligent when they failed to take steps to properly supervise the prisoner and to protect the children from the dangers posed by Nantais.

The assault left the children with psychiatric, psychological and physical injuries, the lawsuit claims.

The Public Guardian is seeking compensation for the boys' pain and suffering, medical and rehabilitation expenses, future care and future wage losses.

Three years after the attack, Nantais was given a 15-year sentence for attempting to murder his wife.

Justice William Grist noted that Nantais was already in Kent for the 1995 attempted murder of his former girlfriend and wasn't offered parole because he posed a significant risk to re-offend.

After the attack, Lutz was afraid to go out in public and constantly worried about further attacks, Grist said.

"The stabbing has also had an effect on the boys. Two of them now have left her home. One is in foster care," he said in his ruling.

The lawsuit's allegations haven't been proven in court. The federal government hasn't filed a statement of defence.