The prime minister visited Syria, Saudi Arabia, Jordan, Israel and the Palestinian Authority to try and encourage the revival of peace talks and bolster support for the international coalition against terrorism.
But a spokesman for the prime minister has insisted the trip was worthwhile, saying "it was the right thing to do".
And Foreign Secretary Jack Straw described it as "very, very significant" in helping to get the peace process "back on track".
No compromise
The diplomatic mission will be followed up next week when the prime minister flies to Washington by Concorde to brief President George W Bush.
The message taken from public pronouncements is not encouraging as most of Mr Blair's hosts showed no signs of willingness to compromise.
Amongst critics of Mr Blair's Middle Eastern tour Conservative former Foreign Secretary Malcolm Rifkind dubbed it "unwise".
He said the joint news conference in which President Assad attacked the bombing campaign in Afghanistan was "extremely ill-advised".
But the Prime Minister's official spokesman said: "It's important to have a reality check here.
"We were never going to solve the problems of the Middle East in 48 hours, nor did we ever expect to.
"But the Prime Minister believes it was absolutely the right thing to do, and that the only way forward is through dialogue."
Despite the expression of long-held views in public, there was "work and talking and engagement in private", he added.
That analysis was echoed by Mr Straw, who said: "The value of the trip was to be gleaned from what was said in private."
As he arrived home earlier on Thursday, Mr Blair said: "I think there is the possibility - I would not put it any higher than that - that we can prepare the ground to move the Middle East peace process forward."
He admitted he had no blueprint for talks, but added: "There are all sorts of ideas being discussed - but that is something that has to be discussed privately."
The prime minister also told BBC News that the Arab world understood the need for action in Afghanistan when 6,000 people had been killed in "cold blood".
Mr Blair, who stopped off in Genoa to meet Italian Prime Minister Silvio Berlusconi on his way back from the Middle East, continued: "Their actual worry is one of double standards.
"What they believe is, 'Yes, you care deeply about the American people that died - but you are not prepared to address the injustices that we believe are there with the Palestinians in the Middle East'," he explained.
| : | CLICKABLE MAP | |
Middle East states: Where they stand | ||
"And my response to that is to say, first of all, that you cannot justify through the Palestinian cause what happened in America - but, secondly, we are trying to address the problems and the injustices in the Palestinian region," Mr Blair continued.
Mr Blair said the suicide hijack attacks on the US would "determine many of the attitudes and aspects of foreign policy right round the world for the next generation".
Earlier Mr Blair warned of a "gulf of misunderstanding" between the Arab and Muslim world and the West.
But the 11 September atrocities were unjustifiable, "no matter how passionately people believe in a cause".