The Olympic flame will be cheered be through the grounds of Buckingham Palace by the Duke and Duchess of Cambridge today as it takes in some of the capital's most famous landmarks on the eve of the Games.
A host of celebrities will parade the torch past celebrated London locations including St Paul's Cathedral, Trafalgar Square, Downing Street and the West End a day before its 70-day, 8,000-mile journey comes to a close.
Scout volunteer Jon Sayer will have the honour of carrying the flame to the gates of the Queen's official London home this evening where he will meet the Duchess.
The 33-year-old, described as an inspirational helper who last year saved the life of a man who had jumped into a river swollen with rainwater, was chosen to take part in the relay after the Duchess asked for a fellow Scout to participate in this prestigious leg of the event.
Mr Sayer, from Todmorden in West Yorkshire, is one of three volunteers helping to carry the Olympic flame through the palace the day before the Queen officially opens the Games.
William nominated his charity Mountain Rescue to take part and John Hulse was given the honour, and Wai-Ming Lee from MapAction was picked after Prince Harry, the organisation's royal patron, put it forward.
The three royals are ambassadors for Team GB and ParalympicsGB and will be joined at the leg by 40 athletes from the Team GB Ambition Programme - which aims to encourage future sports stars