LONDON (Agencies) - Former British prime minister Tony Blair said Friday there had been no covert deal with then US president George W Bush to invade Iraq in 2003, and robustly defended his decision to take Britain to war. Appearing before Sir John Chilcots panel, unrepentant and unashamed Blair insisted he had backed war because Iraqi leader Saddam Hussein had flouted UN resolutions, not because he wanted regime change. Blair, who looked nervous at times as the hearing began, arrived early and entered by a back door amid heavy security and large numbers of police on standby. He told the inquiry that he had no regrets about removing Saddam Hussein from power. Asked if he had any regrets, Blair said: Responsibility but not a regret for removing Saddam Hussein. He opened himself up to a charge of misleading Parliament when he told the Iraq inquiry that by any objective analysis the threat posed by Saddam Husseins chemical and biological weapons programme had not increased after 9/11. No evidence has emerged to link Iraq with 9/11, but Blair said the attacks on the United States had changed the calculus of risk for the transatlantic allies. Up to September 11, we thought he (Saddam) was a risk but we thought it was worth trying to contain it, Blair said. The point about this act in New York was that had they been able to kill even more people than those 3,000, they would have. And so after that time, my view was you could not take risks with this issue at all. Blair said he was concerned that the risk remained today, referring repeatedly to concerns over Irans nuclear programme. However, as part of that analysis Blair conceded that the threat posed by Saddam Husseins purported programme to develop weapons of mass destruction (WMD) had not actually grown - only the understanding of that threat. Striking a defiant note in a six hour grilling by the Iraq inquiry, he insisted it was right to remove Saddam Hussein and said he would do it again. He rejected claims he manipulated intelligence to justify the invasion. Inside, sitting before the panel in a navy blue suit and red tie, he was asked whether he had pledged Britains support for war during a private April 2002 meeting with Bush at the presidents ranch in Crawford, Texas. Blair denied this, saying he had told Bush we are going to be with you in confronting and dealing with this threat posed by Saddams suspected programme of weapons of mass destruction (WMD). How we did that was an open question, and even at that stage I was raising the issue of going to the UN, he said. However he confirmed they had discussed the military option. There was a general discussion of the possibility of going down the military route, but obviously we were arguing very much for that to be if the UN route failed. But there was no dissembling about their talks, Blair said. The position was not a covert position, it was an open position. Blair admitted that a key British government dossier of intelligence about Iraqi WMD in September 2002, which helped make the case for war, could have been clearer. He said the central claim Saddam could launch WMD within 45 minutes should have been corrected. But he said the post-war planning had been flawed. The planning assumption that ... everybody made was that there would be a functioning civil service. Contrary to what we thought ... we found a completely broken system, he said.