George Monbiot was led away as the tried to make his citizen's arrest
Campaigner George Monbiot said he would continue his attempt to serve arrest paper on politicians involved in the decision to go to war in Iraq.
He was unable to make a citizen's arrest of former US ambassador to the UN John Bolton at the Hay Festival.
Mr Monbiot was dragged away by security as he tried to approach Mr Bolton, who was at the festival for a talk.
Mr Bolton said Iraq had "time and time again" shown it was not in compliance with the ceasefire resolution
Speaking afterwards, Mr Monbiot said he planned to pursue former PM Tony Blair.
He said he considered Mr Blair and other leading politicians to be war criminals who had breached international law by their involvement in the decision making process which led to the Iraq war.
He said he had given a dossier of evidence on Mr Bolton - who was President Bush's representative at the United Nations during the time of the Iraq War - to Dyfed-Powys Police ahead of his attempt to present his charge sheet.
Mr Monbiot, who now lives in Machynlleth in Powys, is a leading environmental and anti-war campaigner and journalist.
He said: "I'm aware that I've made what I believe is the first attempt ever to arrest one of the perpetrators of the Iraq War, and I believe that is a precedent and I would like to see that precedent followed up."
Last year he published a book entitled Heat, which calls on the public to make serious changes to their personal lives in order to combat global warming.
In an earlier question and answer session at the event, Mr Monbiot asked Mr Bolton what distinguished him from a Nazi war criminal.
Mr Bolton replied that in exchange for a ceasefire on the Gulf War, Iraq had been required to do a variety of things including a declaration of weapons of mass destruction and the elimination of those weapons.
"By consistently refusing to abide by Resolution 687, Iraq demonstrated it was time and time again not in compliance with the ceasefire resolution," said Mr Bolton.
"It's a fairly straightforward argument, when one party is not in compliance other parties are freed from their obligation under that resolution as well.
"That's one legal justification, the second is the right of self defence. There are others too."
He added: "You're wrong as a matter of law and you're wrong as a matter of fact."
Earlier in the event, asked what he felt had gone right in Iraq, Mr Bolton said: "The first and most important thing is that the fascist dictator Saddam Hussein is dead and his regime is dead."
Mr Bolton said he did not believe the full story on whether or not there were weapons of mass destruction in Iraq was known.
He said that while there was no physical evidence, "we know up until the overthrow of the regime Sadaam kept over 1,000 nuclear scientists and technicians together who were paid a salary and expenses".