Tony Blair Steps Down

President Bush is about to lose his closest foreign ally.

Tony Blair announced today he will step down as prime minister of Great Britain on June 27, 2007. Blair's Labour Party will announce a successor in the coming weeks.

The prime minister leaves office with the war in Iraq casting a long shadow over his political legacy.

ABC's Gloria Riviera has more from London.

After just over a decade in office, Blair believes the time to move on is now.

"Today I announce my decision to step down from the leadership of the Labour party," Blair said.

In 1997, at age 43, the press dubbed him boyish but Blair's victory put an an end to 18-years of conservative rule. He called it a "new dawn."

A close alliance with President Clinton led to military success in Kosovo in 1999 when Blair won praise for his leadership. Later that year, he helped his country heal and won hearts with a simple phrase.

"She was the people's princess," Blair said.

After Sept. 11 Blair made sure his new ally, President Bush, knew where he could turn.

"America has no better friend than Great Britain," Bush said.

With the deepening crisis in Iraq, Blair's popularity has spiraled downward. Today he called the situation there "unrelenting and costly." He also made amends.

"Hand on my heart, I did what I thought was right," Blair said.

Many agree Britain is significantly better off thanks to Blair. He said he has even higher hopes for the country's future.

Gloria Riviera, ABC News, London