Tony Blair's announcement on Wednesday that after eight years he was stepping down as special envoy of the international Quartet to the Israel-Palestine diplomatic process was rather underwhelming.

His role - never well-defined - can hardly be described as a success story.

He leaves the two sides incapable of agreeing even on the terms for fresh talks and the Palestinians planning to unilaterally announce the establishment of an independent state.

Over the years, Mr Blair focused on economic programmes designed to improve the lives of Palestinian citizens and advising the Palestinian Authority on governance issues.

He had some successes, particularly in building local business partnerships and overcoming Israeli trade restrictions, but much more was expected from a man of Mr Blair's stature.

Ultimately, Mr Blair's mission was doomed by a list of countervailing circumstances. Away from Downing Street, the shining image of the only Labour leader to have won three general elections was quickly tarnished by the dismal aftermath of the Iraq War.

In early 2009, he lost his big ally in the White House, George W Bush, and a year later, with the Conservatives in power, his political backing at home was also greatly diminished.

The awkward Quartet structure afforded him little influence and, with competition from the US and the EU's beefed-up foreign service, he had little room to manoeuvre.

His good ties in the Israeli government helped him push through some financial initiatives, but that relationship and Mr Blair's reluctance to voice criticism of either side in public made him a convenient hate-figure in much of the Arab press.

Mr Blair bears some of the responsibility himself for accepting a role he was only intending to fill part-time. His other high-profile work and lucrative private contracts made it nearly impossible to overcome the image of a global gadfly. And yet, blaming him for not solving the Israel-Palestine conflict is unfair. Serving presidents and UN chiefs had more power and resources than envoy Blair and fared no better. Few are thanking him now but he has worked to try to make lives better for ordinary people in the region, and in some places succeeded. That's a lot more than many other potential "peacemakers" can say for themselves.