Jail for man who defaced Queen's portrait

A fathers' rights campaigner who defaced a portrait of the Queen by Australian artist Ralph Heimans has been sentenced to six months jail by a British judge.

Tim Haries was found guilty in January of defacing the portrait with purple spray paint last June while it was hanging in Westminster Abbey.

Crown court judge Alistair McCreath on Wednesday said Haries, 42, had made a "carefully considered decision" that he would gain publicity for himself and his cause by targeting the Diamond Jubilee portrait.

"You caused damage to the painting, disappointment to those who had come to see it, cost to the Abbey and their insurers in putting it right and almost certainly some degree of offence to many people who would regard an attack on a portrait of the monarch as unacceptable," the judge said in sentencing Haries.

The father-of-two has previously stated he scrawled the word "help" on the STG160,000 ($A293,900) portrait in mid-2013 to protest against the "social catastrophe" of fathers not being allowed access to their children.

The court on Wednesday heard it cost STG9200 to repair the work which is now back on public display.

Sydney-born Heimans has previously said he was "extremely shocked" when he heard his portrait had been vandalised but was thankful Her Majesty's face was not defaced.

Judge McCreath said the opportunity to have close access to works of art was greatly valued by many people.

"Those who act as you did put that opportunity at risk," he told Haries, an electrician from South Yorkshire, at Southwark Crown Court.

After the sentence was handed down supporters yelled out in court: "Shame on you" at the judge and "My son is worth more than a painting".