The Olympic Flame has arrived in the UK ahead of a 70-day tour of the country.
Footballer David Beckham, the Princess Royal, Lord Coe, chairman of Games organisers Locog, and London Mayor Boris Johnson flew from Athens, Greece, with the flame.
They were on board British Airways flight BA2012, a gold-liveried plane named The Firefly.
The Olympic Flame was held in four different lanterns, which were fastened into specially designed cradles in seats 1A and 1B for the near four-hour flight from Athens.
The Airbus 319 jet landed at 7.25pm at Royal Naval Air Station Culdrose, near Helston, Cornwall.The Princess Royal carried the lantern containing the flame from the aircraft, accompanied by Beckham, who hopes to play for the Team GB football squad, Lord Coe, Mr Johnson and five British sporting teenagers.
A welcoming party including Deputy Prime Minister Nick Clegg greeted the delegation as they stepped off the plane.
Once on British soil, the distinctive gold London 2012 torch was lit from the lantern and was passed to former England captain Beckham.
He then climbed on to a stage and used the torch to light a cauldron at the air-sea rescue base, where it will burn overnight.
The ceremony was broadcast live on the BBC's The One Show, presented by Chris Evans.
More than 500 guests were present at Culdrose, which is home to most of the Navy's Merlin and Sea King helicopter squadrons.
Lord Coe said: "The arrival of the Olympic Flame on home soil is a magical moment for any host country.
"It will connect millions of people around the UK to the Games in a unique way and allows us to celebrate the best of the UK and its people."
Mr Clegg said the Torch relay would allow Britain to showcase itself to the world.
He said: "Today, the Olympic Flame begins its journey across the nation. Eight thousand people will pass it from hand-to-hand, a human chain that reaches the length and breadth of Britain.
"It will visit a thousand towns, and be seen by millions; with every step, the excitement will build.
"And 10 weeks from now, the world will watch as the flame arrives at the new Olympic Stadium, bringing with it the hopes of a nation.
"This Games is for everyone. Between now and the Opening Ceremony, we have a chance to showcase our sporting heritage, our people and our culture, the things that made us such a great choice for the 2012 Olympic Games."
Mr Johnson said: "This is a fantastic moment for the London Games.
"With every day of the Torch relay, the excitement will build around the country as we look forward to this fantastic festival of sport and culture.
"It also signals the beginning of delivering the wonderful post Games legacy we have promised Londoners that continues to build on the jobs and economic growth that are already benefiting every corner of the capital."
Captain Willie Entwisle, commanding officer of RNAS Culdrose, said: "We are honoured to have been chosen to welcome the Olympic Flame into the UK and also to be able to help it start its very special journey around the whole country.
"All of our personnel, be they part of the search and rescue squadron who will be giving the Olympic Flame a 'lift' to Land's End, those training for frontline operations or even those who are currently supporting the Royal Navy across the globe, are very proud that our air station has been chosen to play a part in the build up to the London 2012 Olympic Games.
"We are delighted that the Fleet Air Arm, the Royal Navy's Flying Force, has been asked to play such an important role in this once-in-a-lifetime event."
Meanwhile, to welcome the Olympic Flame to British shores, the giant antennas at Goonhilly Satellite Earth Station were lit up in red, white and blue.
The coloured lights were beamed from each of Goonhilly's three largest 30-metre dishes as the flame arrived at RNAS Culdrose.
The station, near Helston, has a place in Olympic history as it received the UK and Europe's first colour TV transmissions from the Olympics at the 1968 Mexico Games.
It is also celebrating this year the 50th anniversary of receiving the very first transatlantic TV transmissions in July 1962 via the famous Telstar satellite.
The Olympic Torch will remain overnight under guard at RNAS Culdrose before being flown by the 771 Naval Air Squadron Sea King helicopter to Land's End on tomorrow morning for the start of the relay.
Lieutenant Commander Richard Full will carry a lantern to the world-famous signpost at Land's End, where the first torch will be lit.
Three-times Olympic gold medal winning sailor Ben Ainslie, who grew up in the nearby harbour town of Falmouth, will be the first of 8,000 torchbearers who will carry it across the country.
After running 300 metres he will pass the flame to 18-year-old Anastassia Swallow, who has represented Great Britain four times internationally as a member of the junior British surf team.
The other torchbearers at the UK's most westerly point will be Eric Smith, 76, Victoria Smith, 16, and Stephen Brady, 59.
Forecasters are predicting that the weather will be damp and drizzly as the relay begins but will brighten up later.
Brendan Jones, a forecaster for MeteoGroup, the weather division of the Press Association, said: "At Land's End it will be windy with patches of light drizzle.
"Across Cornwall and Devon it will be cloudy but there will be sunny spells throughout the day.
"There is a risk of light patches of drizzle but the torchbearers would be very unlucky to catch a shower."
The torch visits the four nations of the UK before being carried into the Olympic Stadium in Stratford on July 27 for the opening ceremony of the Games.
It will travel 8,000 miles through 1,019 cities, towns and villages, on foot or in convoy, and drop in at UK landmarks like the Giant's Causeway and Stonehenge.
It will be carried by bearers, or taken in a convoy, and will also be transported by boat, bicycle, tram and train.
The flame, meant to represent purity, was kindled from the rays of the sun using a parabolic mirror in a ceremony on May 10 at Olympia, the home of the ancient Olympic Games.
It was taken on a 1,800-mile relay around Greece before being handed over to the Princess Royal during a rain-soaked ceremony last night at the Panathenaic Stadium, venue of the first modern Olympics in 1896.
The flame was handed over to London to host the Games for the third time since the birth of the Olympics - in 1908, 1948 and now 2012. No other city has staged the Games three times.
There were loud cheers when Beckham, who is also an Olympic ambassador, lit the cauldron.
Princess Anne then went on a walkabout to meet some of the many people who had been invited to watch the arrival of BA2012.
Beckham, Lord Coe and Mr Johnson then made an appearance on BBC1's The One Show, which was broadcasting the ceremony live.
Speaking to the BBC after touching down, Mr Johnson said that over the next 70 days the pressure would be on "to get it right".
He said: "Every step of the torch relay now makes the pressure on us even greater to deliver a really good Games."
Britain was going through tough times and "we want to get the benefits of those Olympic investments for a long time to come", he added.
He also praised Beckham for being an "amazing campaigner" and an "incredible ambassador".
Lord Coe said: "It's just suddenly come home this is the first time this has happened in this country for 64 years...
"I have no doubt nobody's going to sit this dance out."
In 70 days' time there would be "great big British moments in British venues", which would encourage young people to take up sport, he said.
"The challenge is to make sure in 10 years' time they're still in sport," he added.
Reporters quizzed Beckham as he met many of the crowd who had been invited to watch the arrival ceremony.
Asked what he thought about his role in the ceremony, the footballer said: "Amazing, amazing day, very proud. Unforgettable."
(reopens) The celebrations were brought to a close by The Band of Her Majesty's Royal Marines from the Commando Training Centre.
They performed the Beat Retreat, a ceremony that has its origins in the Middle Ages.
On hearing the drums, soldiers would return to their quarters and sentries would be posted for the night.
The sequence ended with the playing of the evening hymn and the lowering of the Naval ensign. The Olympic Flame was then returned to its safety lantern and departed with the band to be stored safely overnight.