Royal family members have welcomed the Olympic torch to Buckingham Palace, on a day when large crowds gathered in London to watch the flame on its penultimate day of its British journey.
The torch also passed through Downing Street, and was taken for a dance by entertainer Sir Bruce Forsyth.
After doubts were raised about the Games, David Cameron said the Olympics would prove "Britain can deliver".
Friday sees the opening ceremony broadcast live worldwide.
The prime minister defended preparations for the Games after US presidential candidate Mitt Romney told TV network NBC stories about difficulties with security guards and threats of border staff strikes were "obviously... not something which is encouraging".
However later, Mr Romney predicted a "very successful" London Olympics after meeting the Prime Minister in Downing Street.
Here, Mr Cameron welcomed the flame as it made a brief stop-over on its way to Buckingham Palace.
The Duke and Duchess of Cambridge and Prince Harry were on on hand to greet three torchbearers - each nominated by their favourite charities - before the flame was carried to Hyde Park.
As the final torchbearer lit a cauldron in front of 60,000 people gathered for a celebratory concert, London Mayor Boris Johnson wished the crowds a wonderful Olympics, and thanked them for their support.
But he also made a reference to the earlier controversy when he told the crowd: "There's guy called Mitt Romney who wants to know if we are ready. Are we ready? Yes we are!"
Earlier, Sir Bruce Forsyth held the golden torch outside the BBC's White City buildings in west London - site of the stadium that hosted the first London Olympics in 1908.
He was handed the flame at the point where the stadium's finishing line once stood by Antoine de Navacelle de Coubertin, a great-grandnephew of the founder of the modern Olympics, Pierre de Coubertin.
"I have been waiting for this for 84 years and I have finally done it, I have carried the Olympic torch," Sir Bruce said.
At a morning press conference in front of the Olympic Stadium, Mr Cameron said the enthusiasm which had greeted the torch relay over the last two months showed they were not a London games, not an England games, but a United Kingdom games.
He added: "Let's put our best foot forward, we're an amazing country with fantastic things to offer. This is a great moment for us, let's seize it."
On Friday, the Olympics will be officially opened by the Queen and the torch's journey will come to an end during the opening ceremony.
A unanimous decision has been made over who will light the Olympic Stadium's cauldron, Locog said, but it will be kept secret until the ceremony.
In other developments:
- Great Britain's men's football team drew 1-1 with Senegal at Manchester's Old Trafford ground.
- Long queues outside St James's Park in Newcastle meant some football fans missed the start of Mexico v South Korea
- The PM met David Beckham at Downing Street to discuss how to tackle world hunger. It came ahead of a "hunger summit" on the final day of the Games, Sunday 12 August
- A planned strike by East Midlands Trains (EMT) during the Games was called off after a pensions dispute was settled
- Locog apologised after an official football programme listed Welsh footballer Joe Allen as English. It said the error would be corrected for Team GB's next match
- Taiwan's flag was removed from a display of national colours to mark the Olympics in London's Regent Street after a complaint by China, which claims sovereignty over the island. It was replaced with that of the Chinese Taipei Olympic Committee, under which Taiwan's athletes compete. London 2012 organisers said the business association behind the display decided to put up the "correct flag... the one used for Olympic Games".
- A global investment conference in London kicked off a series of business summits intended to showcase the UK and attract investment during the Games
- A new record for arrivals at Heathrow is expected to be set on Thursday, with up to 125,000 incoming passengers