Demonstrators harassed Saudi Arabia's King Abdullah on Tuesday during a state visit being overshadowed by criticism of the kingdom's human rights practices and his comments that Britain has failed to do enough to stop terrorism.

Queen Elizabeth II welcomed Abdullah, who reviewed an honor guard on Horse Guards Parade before taking a carriage to Buckingham Palace. Protesters gathering nearby carried banners that condemned government "hypocrisy" and said: "You can't do this in Riyadh."

Before Abdullah arrived on Monday for the first state visit by a Saudi king in two decades, he accused Britain of failing to act on intelligence that might have prevented the 2005 London transit bombings, triggering debate about the kingdom's response to terrorism.

British officials denied the king's claims, saying they received information from Saudi officials about an apparently separate attack, which bore no similarities to the London transit bombings in which 52 commuters and four suicide bombers died.

"For King Abdullah to tell the world, as he did in a BBC interview yesterday, that Britain is not doing enough to counter 'terrorism,' and that most countries are not taking it as seriously as his country is, is really pushing it," veteran Middle East correspondent Robert Fisk wrote in a front-page column in The Independent newspaper.

"Weren't most of the (Sept. 11, 2001) hijackers from, er, Saudi Arabia? Is this the land that is really going to teach us lessons?"

The visit by Abdullah, 82, had a rough start even before his remarks. The acting leader of the opposition Liberal Democrats, Vince Cable, promised to boycott the visit to protest Saudi Arabia's human rights record, especially concerns over torture, public executions and discrimination against women.

Activists pointed to executions, floggings, detention of critics without charge and violence against women among their complaints about the kingdom.

Amnesty International said court proceedings in Saudi Arabia fall short of international standards for fair trials, and take place behind closed doors.

Anti-arms trade campaigners promised to demonstrate, angered by Britain's decision to cancel an investigation into allegations that a Saudi royal received kickbacks as part of an arms deal with Britain's BAE Systems PLC.

"I think the visit sends the message that the UK Government isn't concerned about human rights in Saudi Arabia," said Symon Hill from the Campaign Against The Arms Trade.

"It also sends the message that the government will put the arms trade and BAE ahead of human rights."

Hill criticized Prime Minister Gordon Brown for taking on human rights abuses in countries like Zimbabwe, while ignoring Saudi Arabia.

"It's hard to think Britain can have an influence in the world criticizing (Robert) Mugabe's despotism if the Saudi dictator is welcomed to a banquet at Buckingham Palace,"

Abdullah, who is also prime minister, is expected to meet with Brown on Wednesday. They plan to discuss terrorism, the Middle East peace process, Iraq, Iran and Lebanon, a foreign office official said.

He will also meet with David Cameron, the leader of the main opposition Conservative Party.

Abdullah's comments appeared to be an attempt to distance himself from the extremists and at the same time pre-empt attacks on Saudi Arabia's record of fighting terrorism, analysts said.

The Saudi royal family's legitimacy depends on a radical version of Islam known as Wahhabism — the same strain of the religion that has inspired Usama bin Laden and other Al Qaeda militants. The Saudi royals face the delicate task of maintaining the approval of the same clerics who inspire the terrorists.

Bob Ayers, a London-based former U.S. intelligence officer, said it was inconceivable that British authorities would ignore Saudi intelligence that gave early warning of the London bombings.

By making such a public accusation, the king might be trying to separate himself from the extremists and pre-emptively deflect any British criticism of Saudi anti-terrorism efforts, he said.

"By saying we've been very aggressive and the British have been letting us down, he kills two birds with one stone," Ayers said.