John Bolton, the former US ambassador to the United Nations, has escaped an attempted citizen's arrest as he appeared at the Hay Festival.
Security guards blocked the path of columnist and activist George Monbiot, who tried to make the arrest as Mr Bolton left the stage.
The former ambassador - a key advisor to President George W Bush who argued strongly in favour of invading Iraq - had been giving a talk on international relations to more than 600 people at the literary festival.Mr Monbiot was blocked by two heavily-built security guards at the end of the one-and-a-half hour appearance, before he could serve a "charge sheet" on him.
After being released by the guards the columnist - a fierce critic of the 2003 American-led invasion - made a dash through the rain-soaked tented village in a failed attempt to catch up with Mr Bolton.
A crowd of about 20 protestors, one dressed in a latex George Bush mask, chanted "war criminal" as Mr Bolton was ushered away.
Mr Monbiot said moments later he was "disappointed" that he had been blocked from making the citizen's arrest.
"This was a serious attempt to bring one of the perpetrators of the Iraq war to justice, for what is described under the Nuremberg Principles as an international crime," he said.
During Mr Bolton's talk, to a packed-out audience, Mr Monbiot had asked Mr Bolton what difference there was between him and a Nazi war criminal.