The Paralympic Flame has arrived in London ahead of the opening ceremony at the Olympic Stadium in Stratford.
After making its way through Piccadilly Circus and down Regent Street the flame arrived in Trafalgar Square to loud cheers.
Its was carried by Baroness Tanni Grey-Thompson, GB's most successful Paralympian with 11 wheelchair racing gold medals.
The torchbearing team also included former boxer Michael Watson and Paralympic swimmer Chris Holmes.
Sky's Mark Stone in Trafalgar Square said: "This is one of a number of locations where people who have not got tickets for the actual ceremony itself can come down and watch the ceremony on a big screen. Just before that there will be live music down here."
The torch continued its marathon journey to Stratford past Downing Street, the Houses of Parliament and the London Eye - some of city's most famous landmarks.
Earlier it stopped at the Shree Swaminarayan Hindu temple in Neasden, Brent, before making its way past the Abbey Road crossing made famous by the Beatles, Lord's Cricket Ground and London Zoo.
As the relay was running two hours late for most of the day, a break-away torch was created at City Hall.
Organisers said they were hopeful the relay would finish in time for the opening ceremony, and the second flame was purely a "contingency".
By the time it reaches the Olympic Stadium, the relay will have featured 580 torchbearers in teams of five, covering a distance of 90 miles.
The flame was lit from the flames of the four host nations in a ceremony at Stoke Mandeville in Buckinghamshire, where the Paralympic movement began in 1948.
The ceremony was opened by Lord Sebastian Coe who said he was "so excited" the Games were finally coming home.
Lord Coe, the head of London 2012 organisers Locog, also paid tribute to neurologist Dr Ludwig Guttman, the founder of the Paralympics.
Dr Guttman's daughter, Eva Loeffler, also spoke to the crowd. She said of her father: "Seventy years ago he said 'I dream of the day when disabled people will take part in the Olympic Games'.
"His dream has been realised this year and he would be immensely proud to see the Paralympic Games which will be open in London.
"Even he could not have dreamt that lighting a spark in the hearts, minds and bodies of Paralympians would grow to be the amazing spectacle we are about to witness."
Paralympic gold medallist Tony Griffin carried the English flame during the ceremony, while Paralympian Christopher Channon took the Scottish flame on to the stage.
Special constable Darren Ferguson carried the flame for Northern Ireland after being recognised for going to the aid of a man who wanted to take his own life.
Marsha Wiseman bore the Welsh flame after being nominated for the work she has done to promote the Paralympic Games.
The four flames were struck last week by young disabled and non-disabled Scouts on the four highest mountain peaks in each of the four host nations - Scafell Pike in England, Snowdon in Wales, Ben Nevis in Scotland and Northern Ireland's Slieve Donard.
The opening ceremony at Stratford will usher in 11 days of competition by nearly 4,300 athletes from 166 countries. They will compete for a total of 503 medals across 20 sports.
A record 2.4 million tickets have been sold for the London Paralympics, with half a million going to visitors from abroad. A further 10,000 will go on sale each day during the event.