The statue had already proved controversial

The Court of Appeal said Paul Kelleher's case raised a point of law of general public importance.

Kelleher, 38, of Isleworth, west London, served 42 days of a three-month jail sentence imposed in last February.

Last year the political protester lost an appeal but on Monday he was given leave to petition the House of Lords.

The 8ft Italian �150,000 marble sculpture was at London's Guildhall, on loan from the House of Commons, when Kelleher attacked it with a cricket bat and, when that failed, a metal pole from a crowd barrier.

It was irreparably damaged.

Last November, the Court of Appeal said the trial judge had correctly told the Southwark Crown Court jury that Kelleher had no defence in law.

Kelleher wanted to make a political point

But it said the judge went too far in virtually directing the jurors to convict, he should have left them to return a formal verdict.

Despite that error no injustice had occurred, the appeal judges said, because Kelleher had admitted all the elements of the offence.

His conviction was therefore "safe".

On Monday, Lord Justice Mantell, Mr Justice Elias and Mr Justice Jack refused Kelleher leave to appeal to the Law Lords, but certified a point of law enabling him to petition the House of Lords for leave.

The question of law was: Can a verdict of guilty ever be considered safe if it results from a direction to convict?