Former Prime Minister Tony Blair's policy in Iraq did not work. The ousting of Iraq's leader did not improve the state of Iraq, nor did subsequent foreign policy against Iraq. However, the war in Iraq reduced the threat of civil war, unlike Syria. It seems like if you remove one battle in the middle east, you begin another. The goal is to stabilize and govern the country. The issue is a complex one.
The Iraq War is pretty unanimously viewed as a mistake, in terms of execution if not in purpose. The difference is that the American public has the "excuse" of post 9/11 paranoia, whereas Tony Blair and the British government were willing pawns of George W. Bush's agenda. Blair was a pathetic leader, and history will look on him as a sycophantic patsy, desperate for attention from the most powerful nation on Earth.
That lying scheming warmonger is waaaaay past being plain "wrong". The act of invading and occupying Iraq by itself was wrong and bad enough, but when the truth about deliberately manufacturing false evidence about WMD as a pretext and justification, and then continuously carrying out mass-media propaganda by forcing the hand of all media houses (so much for democracy, freedom of speech and independence in the West), and the scandal with alleged suicide of the brave hero who has outed Blaire's blood/oil thirsty regime... plain and simple, Blair became a war criminal. A genocidal soulless man with blood of hundreds of thousand innocent Iraqi lives on his hands (plus add the Yugoslavia bombings as well). And as we can see, the deahts and horror in the Iraq and Middle East do not stop and only escalate to this day. He should be put on trial in Hague, and sentenced to life in prison. End of discussion.
Hindsight is a fantastic thing and maybe in retrospect it was the wrong decision to go to war but at the time it felt right. I believe that it would have been wrong to stand aside while a dictator rules his country through fear and threats. Many Iraqi lives were saved and given the intelligence that was to hand it was the right decision.