Political Correspondent Robert Merrick gives his view of Tony Blair's success - and his biggest failure.

TONY Blair has insisted history will judge him far more kindly than will today's obituaries marking his resignation from power. He can only pray he will be proved correct.

The truth is he will leave No 10 branded a war criminal by many and with the stain of being the first prime minister in history to be questioned by police as part of a corruption inquiry.

Furthermore, there is no disguising Mr Blair's anger at being forced from office far earlier than the "full third term" he pledged to serve, by Labour MPs who owe their careers to him.

It is an astonishing fall from the sunlit day when he entered Downing Street with the goodwill of almost all the nation, a young leader with unmatched political gifts at his disposal.

In the days following May 2, 1997, all of Britain appeared to be grinning as people celebrated - almost in disbelief - the eviction of the discredited Tories. So where did it all go wrong?

Before we answer that question, however, we should explore where it went right - because there are many, many areas where it did.

Britain in 2007 has better healthcare, better schools, more jobs, less crime, fewer poor pensioners, fewer children in poverty, better housing estates and more attractive cities than a decade ago.

The - sometimes dramatic - improvements are all around us, in the thousands more doctors, nurses and teachers, disappearing waiting lists, smaller classes and modern classrooms.

There is also a minimum wage, tax credits for low earners, massively expanded childcare, new maternity and paternity rights, Sure Start children's centres, devolution to Scotland and Wales.

The achievements are even more impressive when you consider how little was promised in the 1997 manifesto - an ultra-cautious document, with far more ruled out than ruled in.

Of course, not all the money has been wisely spent, but anyone disputing the fruits of all that investment poured into public services is either very young, or has a very short memory.

The greatest tribute is paid by the Tories, forced, in desperation brought on by repeated defeat, to adopt the mantra: "If you want to defeat your enemy, sing his song".

They want to scrap the Human Rights Act and the fox-hunting ban, but almost everything else is here to stay. Forget large-scale tax cuts - public spending comes first now.

From a party perspective, Mr Blair made Labour - out of office for most of the 20th Century - the natural party of government, winning an unprecedented three general elections in a row.

When Britain is next struck by a collective moment of tragedy -remember the July 7 bombings and the death of Diana -his ability to articulate the view in the nation's living rooms will be missed.

But... the first but is how much of this is down to Tony Blair? The money flowed because the government was not shipwrecked by an economic crisis, but that's Gordon Brown's achievement.

Furthermore, some of the successes Mr Blair likes to reel off at the despatch box - the minimum wage, tax credits - he actively opposed.

The Prime Minister represents a North-East constituency that had fallen far behind the booming South under the Tories, yet he insisted the North-South divide doesn't matter.

More than that, there is the feeling that 1997 was a once-in-a-generation opportunity to change Britain for ever, just as the 1945 government did, rather than aim for mere incremental improvement.

Recently, I heard Mr Blair, asked the question: "What are you most proud of?" He fumbled around for answer before settling on Britain being "more modern".

Not fairer, or more equal - traditional Labour values - or even more contented, but more modern. A criteria entirely free of any moral value.

It is no coincidence that his crowning achievement is not in domestic politics, but in Northern Ireland, where his personal commitment and dogged determination made the difference.

Also, Mr Blair was the politican who was going to restore trust after all that Tory sleaze. With the cash-for-honours' scandal dragging on, that seems like a bad joke now.

Above all else there is the near-unimaginable horror of Iraq, for if the domestic record was one of cautious success, the foreign policy was a catastrophe.

Most Labour figures simply cannot understand what drove Mr Blair to hitch his wagon to George Bush's crusading chariot and join a "battle between good and evil".

It has led to daily bombings and beheadings from Baghdad to Basra - most now unreported - and the slaughter of hundreds of thousands of Iraqis.

Week after week in the Commons, Mr Blair reels off the names of the latest British dead from a war that can no longer be won. Only the embarrassment of withdrawal beckons.

When no weapons of mass destruction were found, it was a fatal blow to a "a pretty straight kind of guy" who was now exposed, on all those T-shirts and placards, as "Bliar".

It is now beyond dispute that Mr Blair had secretly committed himself to removing Saddam as early as April 2002, when he met President Bush at his ranch in Texas.

Yet he spent the next year before the March 2003 invasion denying both that the conflict was inevitable and that Britain was preparing for war.

The late Robin Cook, then Foreign Secretary, knew the infamous 45-minute claim was false because he knew it refered to tactical weapons, not to ballistic missiles that could be fired at an enemy beyond Iraq's border.

Mr Blair still wants us to believe he did not know because he did not even ask his intelligence chiefs. He says he acted honestly, yet Lord Butler found the evidence on Saddam's weapons "limited, sporadic and patchy". Mr Blair had called it "extensive, detailed and authoritative".

The deceit continued long after the invasion. No 10 trashed the Lancet's report of 655,000 Iraqi dead, yet the MoD's chief scientific advisor considered its methods "close to best practice".

Many wrongly labelled Mr Blair a US "poodle" when, in fact, he shared the neo-con, good- ersus-evil world view. It's hard to see how that makes his actions less worthy of condemnation.

There is, therefore, a certain justice that the Prime Minister is being forced out prematurely because he sided with the neo-cons once too often, even for his MPs.

When Mr Blair backed Israel's murderous assault on Lebanon - the civilian death toll topped 1,000 - it further shattered Britain's reputation abroad and prompted September's half-coup.

Nevertheless, history will surely find it bizarre that the Labour party allowed Mr Blair to remain in office for years after the Iraq lies - and the disaster they wreaked - were laid bare.

There are shiny new schools and hospitals at home, but that won't be the first line of his legacy, not when there is slaughter on a medieval scale, a terrorist playground created and Britain is a terror target.

Everybody was supposed to be famous for 15 minutes, but Mr Blair will forever be famous for 45 minutes,