Attendants carried the flame in a lantern
The Olympic flame has arrived in London ahead of a torch relay when it will be paraded through the streets.
Chinese ambassador Fu Ying and Minister for the Olympics Tessa Jowell were at Heathrow to welcome a delegation who carried a lantern holding the flame.
On Sunday 80 athletes, entertainers and dignitaries will carry the torch by relay on a 31-mile long journey through the capital's streets.
Activists critical of the Chinese government have vowed to hold protests.
Speaking after she greeted the Chinese delegation, Mrs Jowell told the BBC she hoped the protests would be peaceful.
She said: "Tomorrow is about celebrating the spirit of the Olympics in a context, yes, of where the eyes of the world are on China and where protest at the relationship between China and Tibet will be very much the focus.
"But what we have to recognise is that Londoners can mark and celebrate the Olympic torch relay without any suggestion the government is condoning what is happening in China."
The Metropolitan Police said 2,000 officers would be mobilised to maintain order along the route of the relay.
A spokesman said Scotland Yard had heard from six organisations, including the Free Tibet movement, the Falun Gong spiritual group and the Burma campaign, which were planning to send a total of up to 500 demonstrators.
Commander Bob Broadhurst said: "There are plans and I would say to those that do come to demonstrate, 'Do so lawfully and we'll allow it, but if you try and disrupt the torch or you try and grab the torch we'll be there to stop you, so please don't do it'."
'Celebration of sport'
Free Tibet spokesman Matt Whitticase said: "What worries me and many other protesters is the way in which China is draping itself in Olympic values and talking about a journey of harmony with this torch relay, whilst at the very same time, as has been reported this morning, the Chinese government is killing Tibetans in Tibet."
Tibetan exile groups claim at least eight people were killed when security forces fired on civilians in Sichuan province, western China, on Thursday, while the state Xinhua news agency says a government official was seriously injured by rioters.
The five-time Olympic gold winner will launch the London relay
Sir Steve Redgrave, Tim Henman, Dame Kelly Holmes and Kevin Pietersen will be among the 80 torch bearers as it is carried miles through 10 London boroughs on Sunday.
But comedian Francesca Martinez pulled out after she decided that taking part would legitimise the Chinese government's role in Tibet.
The torch was lit in Olympia, Greece, last week and will go through 20 countries before being carried into the Beijing Games opening ceremony on 8 August.
The Metropolitan Police will also have Chinese interpreters on hand and any insulting banners will be confiscated, a BBC correspondent said.
There were scuffles between police and pro-Tibet protesters when the torch was handed to Chinese officials in Athens at the end of last month.
Hundreds of Chinese students in the UK are planning counter-demonstrations in support of the Beijing games.
LONDON TORCH RELAY 6 APRIL
1: Wembley 1030BST
2: Ladbroke Grove 1100
3: British Museum 1220
4: China Town 1230
5: Trafalgar Square 1250
6: Southbank Centre 1330
7: Somerset House 1415
8: St Paul's Cathedral 1430
9: Potter's Fields 1500
10: Whitechapel Road 1530
11: Stratford 1600
12: Canary Wharf 1700
13: North Greenwich 1800
Source: Mayor of London