BITISH Prime Minister Gordon Brown has defended the invasion of Iraq but said he regretted that he had not been able to persuade the US to take postwar planning “seriously enough” to ensure a “just peace”.

The prime minister revealed his frustration with US politicians in the build-up to the war when he told the Chilcot inquiry into the Iraq war in London on Friday about his involvement in planning, discussions and decision-making while serving as chancellor (UK finance minister).

In the first hour of his evidence, Brown said the US-led invasion had been the “right decision made for the right reasons”.

Saddam Hussein was a “serial violator” of UN resolutions and a clear message had to be sent to “rogue states” that international law could not be flouted, he added.

He told the inquiry he had not been kept in the dark by the then prime minister, Tony Blair, in the run-up to the invasion, and said he had been convinced by a series of intelligence briefings that Iraq was a threat that “had to be dealt with”. Responding to comments by former cabinet colleagues to earlier sessions of the inquiry, he also maintained he had imposed “no barrier” on funding the military and had tried to place a sharper emphasis on postwar reconstruction.

Brown acknowledged that there were “important lessons” to be learned from the way Iraq had descended into chaos following the invasion. He said he had prepared a paper on the issue as early as September 2002, and had held a number of discussions on how international institutions could be brought into aid reconstruction. The prime minister — who had originally been scheduled to give evidence to the inquiry after the forthcoming UK general election — told the panel “I was determined — and I may say it's one of my regrets I wasn't able to push the Americans further on this issue — that the planning for reconstruction was essential just at the same time as the planning for war if the diplomatic avenue failed.

“We were working on reconstruction and what might be done with what I called earlier the search for a just peace ... we were looking at that early on.” Brown added that he had offered to present a paper as part of cabinet discussions on the matter.

“We were determined to understand how we could get the international institutions involved in reconstruction,” he told the panel.

“We didn't see how it was possible for Britain and America ... without the International Monetary Fund, the World Bank and the UN in the end being involved with reconstruction, to get finance to the order of £45bn of reconstruction.

“So we were focused on this issue of reconstruction and, as I say, I wish it had been possible to follow that through much more quickly in the aftermath of the first few days of the battle.”

Earlier in the inquiry, the former secretary of state for international development Clare Short told the panel Brown had said Britain should play an “exemplary role” in reconstruction, but that funding had not been forthcoming.

— The Guardian, London