Britain is on its second highest terror alert as U.S. President George W. Bush flies in on Tuesday for the start of a contentious three-day state visit. The level of security in “Fortress London” and, specifically, at Buckingham Palace, where the president and first lady will be staying, has been increased for the first time since the September 11 attacks in the United States following warnings of a planned al Qaeda terror attack on the British capital.

The Bush’s will receive a private welcome from Prince Charles when they touch down on British soil on Tuesday evening for the first state visit accorded to an American president.

The president’s formal schedule will begin on Wednesday morning with a ceremonial welcome at Buckingham Palace. On Thursday, Bush will hold talks with British Prime Minister Tony Blair at 10 Downing Street before visiting the Blair’s constituency of Sedgefield in County Durham on Friday.

Iraq, Cuba, Afghanistan and Steel

Although there is no official agenda for the meeting between the two leaders, government officials have speculated that the president and prime minister will discuss a possible deal to appease British complaints about Britons detained in Afghanistan and held without trial in the U.S. base at Guantanamo Bay in Cuba. Bush told the BBC on Sunday: "I'm working closely with Tony to come up with a solution that he is comfortable with."

It is also likely that coalition partners will also announce that the United States will lift tariffs protecting its steel industry which last week were declared illegal.

During the visit, the president will also hold meetings with relatives of British victims of September 11 as well as servicemen who fought in Iraq and Afghanistan.

Security at highest level

The arrival of the U.S. president and his wife in Britain on the first visit since the Iraq war has prompted police and security officials to take unprecedented precautions in light of a British Home Office warning regarding a non-specific plot by suspected North African al Qaeda operatives. It is a threat the authorities are obviously taking very seriously in the wake of the suicide attacks in Istanbul over the weekend which were attributed to operatives of Osama bin Laden’s terrorist network.

"The security is unprecedented because one, the level of the terrorism threat, and two, the nature of the president's visit," said Metropolitan Police chief Sir John Stevens, the most senior police officer in Britain, in a press statement.

Ring of steel

Buckingham Palace, the Queen’s main London residence, will be surrounded by a ring of steel when Bush arrives, while concrete blocks and metal-detector arches are reportedly being placed along Whitehall, the political quarter around the British parliament. Also, the infamous London gridlock is likely to be exacerbated by the closure of a number of roads in the creation of a "sterile zone" around Bush, who will also be shielded by a security cordon.

In a move that will see more armed men on the streets of London than at any time since the end of World War II, a total of 14,000 British police officers -- increased overnight from 5000 -- will be on duty to protect the American president, along with hundreds of U.S. armed guards.

There will also be a large contingent of the plainclothes diplomatic protection squad and the motorcycle escort group, both of which have recently had weapons training to deal with any potential attempt on the president’s life.

Many buildings on London’s famous skyline will have police snipers stationed upon them, covering the main points of the Bush motorcade as it winds it way through the capital. As well as high vantage points, sewers and drains will continue to be scoured for devices until the visit is over at the end of the week.

Fighters on standby for air attack

Painfully aware of what an attack from the sky can achieve, a squadron of the Royal Air Force Tornado F3 air defense squadron is on standby to move closer to London from its base in Norfolk, so as to be ready to intercept any passenger jet hijacked by terrorists. However, the U.S. request for helicopter gunships to hover over Buckingham Palace at all times when Bush is in residence was firmly ruled out.

Police will also be charged with keeping an expected 100,000 protestors away from the president during his stay in London. Supporters of the Stop the War Coalition, the British group who organized an anti-war rally in London that drew more than one million protestors in February, will be joined by several other European anti-war groups -- including France's Non a la Guerre (No to War), Italy's Ya Basta (Enough's Enough) and the Axis of Peace Coalition of France, Germany and Russia.

Bush not welcome, say protestors

"This is the man who is in charge of the administration that's killed 8,000 Afghanis and 10,000 Iraqis," said Ghada Razuki of the Stop the War Coalition. "He is adding insult to injury by coming to our country, and he's going to find out that he's not welcome."

"Our message to Bush is firstly, get your troops out, and secondly, if you think you can go into another country in the same way, think again," Razuki said.

President to be toppled

Along with displaying over 3,000 “Stop Bush” placards as they march through central London, protestors are set to topple an effigy of President Bush in Trafalgar Square in much the same way as a statue representing Iraqi dictator Saddam Hussein was pulled down by U.S. tanks in Baghdad in April.

The Metropolitan Police have hired about 250 mini-vans to ship officers equipped with body-length riot shields, CS gas and batons to the scene if the protests turn violent.

Blair defends invite

However, as the crowds prepared to swarm on the capital, the prime minister insisted on Tuesday that he stood by the decision to invite President Bush to Britain.

“This is the right moment for us to stand firm with the United States in defeating terrorism, wherever it is, and delivering us safely from what I genuinely believe to be the security threat of the 21st century,” he said.

Polls show a divided nation

Despite the prospect of massive public protests, the opinion of the British people as a whole is hard to gauge. In the run-up to the president’s visit, a number of polls were taken to test the current climate. One survey by the British daily Independent showed that some 91 percent of respondents were against Bush’s visit.

Another by pollsters YouGov found that 60 percent of those questioned went as far as branding the U.S. president a threat to global stability, while a poll by The Times showed that 59 percent of its respondents believe that the standing of the US has fallen since Bush took over the White House.

But an ICM survey carried out on behalf of The Guardian newspaper suggested that 43 percent of British people welcomed the president while 36 percent opposed his visit. The same poll showed that more than half of Labour Party supporters questioned (51 percent) approved of the visit, against 34 percent who would prefer the president to stay away.

The security bill for the president’s visit is expected to cost Britain's taxpayers in the range of ₤4 million. That's a hefty $6.7 million (€ 5.7 million) bill for a three-day guest.