Former British prime minister Tony Blair admitted on Tuesday that the situation in Iraq is "not nearly" what he hoped it would be when Britain joined the US-led invasion to depose Saddam Hussein ten years ago.

He said he had made the best of an "ugly" choice between taking action against the Iraqi dictator in 2003 or running the risk that Hussein would launch chemical and biological attacks against his own people or the outside world.

"There are actually significant improvements in many parts of the country for the people, but I agree with you, it's not nearly what it should be," the former Labour leader told the BBC in an interview marking ten years since the invasion.

Around 162,000 people, almost 80 percent of them civilians, were killed in Iraq between the start of the US-led invasion and the withdrawal of US forces in December 2011, according to British NGO Iraq Body Count.

Attacks continue, with 1,500 people killed in violence in Iraq last year according to an AFP toll.

Blair, who stepped down in 2007 after ten years as prime minister, said he thought constantly about the people who lost their lives in the conflict.

"But in the end you're elected as prime minister to take these decisions. The question is, supposing I had taken the opposite decision?" he said.

"Sometimes what happens in politics, and unfortunately these things get mixed up with allegations of deceit and lying and so on, in the end sometimes you come to a decision where whichever choice you take the consequences are difficult and the choice is ugly. This was one such case."

Blair suggested that if Saddam was still in power now and Iraq had seen an uprising similar to those elsewhere in the Arab world, he would probably have been "20 times as bad as (President Bashar al-) Assad in Syria".

He acknowledged the US-led invasion remained extremely divisive, but said: "I've long since given up in trying to persuade people it was the right decision.

"In a sense what I try to persuade people of now is to understand how complex and difficult a decision it was.

"Because I think if we don't understand that, we won't take the right decision about what I think will be a series of these types of problems that will arise over the next few years.

"You've got one in Syria right now, you've got one in Iran to come. The issue is how do you make the world a safer place?"