London ? President Bush, visiting America’s strongest war ally on the eve of an expected major protest in Britain, on Wednesday called on opponents of the Iraq war to put aside any lingering animosity and support the U.S.-led effort to rebuild that nation, saying the world cannot allow democracy to fail in Iraq.

“We did not charge hundreds of miles into the heart of Iraq and pay a bitter cost of casualties, and liberate 25 million people, only to retreat before a band of thugs and assassins,” Bush said.

Bush defended the coalition’s actions in Iraq on the first full day of a four-day state visit to Britain, a day that began with an elaborate, formal welcoming ceremony at Buckingham Palace and ended with the clinking of elegant silver on centuries-old china at a state dinner.

Bush said Iraq demonstrated that the United Nations must be protected from “solemnly choosing its own irrelevance” by nations willing to back the world body’s warnings to rogue regimes with military action.

He challenged the UN to avoid the path of its forerunner, the League of Nations, which, “lacking both the credibility and will,” allowed Adolf Hitler to advance.

“It’s not enough to meet the dangers of the world with resolutions; we must meet those dangers with resolve,” Bush said. He said that the United States remained committed to working with other nations but that results were more important than the “tidiness of the process.”

The demonstrations Wednesday against Bush’s visit were small, though occasionally dramatic, and a bigger demonstration was being organized for today.

On the second day of U.S. President George W. Bush's state visit to London, anti-war demonstrators invoke one of Britain's more gruesome traditions and call for the head of a traitor on a spike. In the background Wednesday is London's Millennium Eye.

The intense security arranged to protect the president was openly mocked when the Daily Mirror newspaper revealed that one of its reporters had been working at Buckingham Palace for two months under false pretenses and, had he been a terrorist, would have been in a position to harm Bush and the queen.

The new “footman” boasted he rode on royal carriages, served tea to the queen and had free rein in the royal residence.

Palace, police and government officials scrambled Wednesday to investigate how the Daily Mirror reporter was hired and assigned duties that reportedly included delivering chocolates to the guest quarters of Bush and his wife, Laura.

Buckingham Palace said it was considering legal action against the newspaper.

The Daily Mirror splashed the story across 15 pages Wednesday, the first full day of Bush’s state visit to Britain.

The newspaper said the infiltration by reporter Ryan Parry exposed “shocking incompetence at the heart of the biggest security operation ever in Britain.”

A Buckingham Palace spokeswoman said the palace was conducting a “full investigation” and had “put in place additional measures to its current recruitment procedures” as a result of the apparent breach.