Updated at 11:10 a.m. ET: LONDON - Olympic athletes, including some from Team USA, had a bad start to the London Games Monday after bus drivers taking them to the competitors’ village in east London got lost.

Kerron Clement, US 400m hurdler and Beijing silver medallist, claimed he spent four hours on a bus after the driver got lost after collecting them from Heathrow airport.

He posted on Twitter:  “Um, so we've been lost on the road for 4hrs. Not a good first impression London. Athletes are sleepy, hungry and need to pee. Could we get to the Olympic Village please.”

Meanwhile, members of Australian contingent of 30 officials and medical staff had to use their iPhones to direct their bus driver after he also became lost.

One of the officials, Damian Kelly, told the Daily Telegraph: "It would have been a great tourist trip if that is what you are here for. “

He said the driver was unable to work the onboard GPS navigation system.

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“One of the doctors on board got [the GPS system] working for him, but then the Olympic Village hadn't been loaded into the system and everyone was trying to find the name of the street that the village was in.

“In the end another physio got out his iPhone and gave directors to the bus driver via his phone."

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Members of the Cuban Olympic weightlifting team arrive at Heathrow airport on Monday.

They were among the first of more than 10,000 athletes and officials due to arrive in Britain this week. Monday was already expected to be the busiest day in the history of London's Heathrow airport, and it was the first major challenge for the road system as the first of several dedicated Olympics traffic lanes also came into operation.

Speaking about the lost buses, London Mayor Boris Johnson quipped: "Clearly they would have had even more of an opportunity to see even more of the city than they might otherwise have done."

Troops everywhere, long lines and moans: A very British Olympic Games

The Daily Telegraph reported that Hugh Robertson, Britain's sports and Olympics minister, apologized to those athletes caught up in the transport problems. He said: "If people have been on buses that have got lost then it is of course regrettable. I am extremely sorry, and clearly the drivers need to know where they are going."

The Games are due to begin in 11 days' time, on Friday, July 27.

More than 500 Heathrow and Locog volunteers, speaking more than 20 languages between them, were welcoming groups of Olympic athletes and officials from their planes at Heathrow.

Approximately 15 percent of baggage on peak days will be large pieces of sporting equipment such as canoes, pole vaults, bikes and javelins and around 1,000 guns and associated ammunition will be arriving with competitors over the coming days.

Read the full story at ITV News

Influx under way
Officials said 236,955 passengers (121,239 arrivals and 115,716 departures) were expected to pass through the airport Monday, compared to 190,000 on an average day. The largest number of arriving athletes is expected on July 24.

Slideshow: Venues for 2012 London Olympic Games

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From Wimbledon to Wembley Stadium to The Dome, a look at the venues for the 2012 London Olympic Games.

Launch slideshow

Approximately 15 percent of baggage on peak days will be large pieces of sporting equipment such as canoes, pole vaults, bikes and javelins and around 1,000 guns and associated ammunition will be arriving with competitors over the coming days.

Dean Brenner, director of the U.S. Olympic sailing team, earlier told ITV News at Heathrow: "We're feeling great, it's great to be in London.

"Obviously we've been working a while for this and now it's time for the big test and we are looking forward to getting to [the sailing team base at] Weymouth for a couple more week of training and getting on with the Games."

The London 2012 Athletes' Village also officially opens Monday with British athletes competing in diving, equestrian, soccer, shooting and swimming expected to be the first to enter.

ITV News is the UK partner of NBC News.

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LONDON -- Benson’s tail wagged lazily as he weaved through the crowds in London’s St. Pancras railway station.

“Good morning ladies and gents, police dog working,” said the pooch’s handler, Graham Rowlstone of the British Transport Police, as the pair strode beneath a soaring glass-and-blue-steel ceiling. “Just making sure it’s nice and safe for you.”

Some travelers and commuters smiled, laughed and said hello to the black lab. A few petted him. But mostly the pair slipped easily through the concourse.

Suddenly, Benson cocked his ears, lifted his tail and picked up the pace. He trotted in front of a nondescript man in a dark blue fleece, sat down and looked up expectantly.

“Good morning, sir. Where are you traveling today?” Rowlstone asked.

It was a drill to show that Benson’s explosives-sniffing skills were still sharp. The dog passed the test and the man in blue – dog trainer and police officer Paul Saunders – dropped a tennis ball, which Benson chewed enthusiastically.

Dealing with threats
As Britain gears up for the estimated one million visitors expected to descend on the city for the 2012 Olympic Games, bomb-sniffing teams like Benson and Rowlstone are preparing to deal with the threats that come with the big crowds.

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Benson is a relative newcomer to the explosives-detection space, which has been long dominated by “proactive” dogs, which concentrate on inspecting places such as lost-luggage departments and suspicious packages left on trains and buses. In other words, they deal with stationary targets. 

About three years ago, the British Transport Police and others began to train so-called passive dogs like Benson, which search for explosives among crowds of people, essentially following a scent until it stops.

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Officer Graham Rowlstone of the British Transport Police pats Benson after he correctly identifies a threat in London's St. Pancras Station.

Bomb-sniffer dogs are an integral part of the system in place meant to keep travelers safe and public transport running smoothly, British Transport Police Inspector Ed Purchase told msnbc.com.

“The dogs are an extended part of the security operation within London and around the country, making sure the railways are safe, members of the public are safe and that we can keep all the transport system open,” he said.

With the biggest and oldest dog unit in the country, the British Transport Police – in charge of policing Britain's railways and subways – know what they’re talking about.

Attack highly likely?
Britain has faced threats to its mass transit systems for well over a century – the first terrorist strike on London’s underground network was in the 1880s.

And just a day after the announcement was made to award the Olympics to London on July 6, 2005, the city suffered its worst peacetime attack when four suicide bombers killed 52 commuters.

Al-Qaida to Occupy: UK preps Olympics security

So it comes as no surprise that the issue of security on the country’s transport system weighs heavily on the minds of the Olympics organizers.

The games will see the U.K.’s largest peacetime security operation involving tens of thousands of security officials, with 13,500 military personnel, 12,000 police and 10,000 private contractors.

Current potential dangers to London come from a variety of sources including al-Qaida and related jihadi groups, right-wing extremists and Northern Ireland-related militants, according to officials.

The U.K.’s alert level is expected to be raised to “severe” during the games, meaning that an attack is considered highly likely, the government says.

Four-legged ambassadors
For Benson and his canine colleagues it will be a busy time. But while they are most valued for their keen noses, the dogs also have a key public relations role to play.

“(The dogs) are a tool … effective across a range of activities – reassurance, engagement with the public and detection – that’s why they’re attractive to us,” Superintendent Philip Trendall, of the British Transport Police's Counter Terrorism Support Unit, told msnbc.com.

“People notice us a lot more,” said Constable Tony Mart, who works with another black lab, named Pete. “They will always see a police officer with a dog. The interaction with the public is great,” he said.

British Transport Police

Benson the police dog even has his own business card.

About a dozen passives have been incorporated into the team over the last three years, Trendall said, but declined to discuss their success rates.

And he says that the dogs’ public-facing role in boosting confidence and good cheer is almost as important as its explosives-sniffing one.

“A machine that people want to come up and give a biscuit to and pat doesn’t exist,” he said.

F. Brinley Bruton is a reporter and editor with msnbc.com in London. Follow her on Twitter.

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