The Archbishop of Canterbury has praised the Queen for dedicating herself to the service of her nation and Commonwealth in a thanksgiving sermon celebrating the Diamond Jubilee.
Dr Rowan Williams told a congregation of leading figures from the UK and overseas that the Queen's decision to devote her life to others has "endured faithfully, calmly and generously" during her 60-year reign.
He also suggested the Jubilee year could be a spur to the nation to follow the example set by the Queen of selflessly helping those around us.
Missing from the St Paul's Cathedral service was the Duke of Edinburgh who was taken to hospital yesterday with a bladder infection.
"To declare a lifelong dedication is to take a huge risk... but it is also to respond to the promise of a vision that brings joy."
His absence is likely to be greatly felt by the Queen and her family during the series of celebrations planned for today to mark the end of the Diamond Jubilee weekend.
Dr Williams mentioned the Duke in his address saying "our prayers and thoughts are very much with him this morning".
The service was a religious acknowledgement of the life of the Queen, who is head of the Church of England and has deeply held Christian beliefs.
The Archbishop told the congregation: "Dedication to the service of a community certainly involves that biblical sense of an absolute purge of selfish goals, but it is also the opening of a door into shared riches.
"I don't think it's at all fanciful to say that, in all her public engagements, our Queen has shown a quality of joy in the happiness of others; she has responded with just the generosity St Paul speaks of in showing honour to countless local communities and individuals of every background and class and race.
"She has made her 'public' happy and all the signs are that she is herself happy, fulfilled and at home in these encounters.
"The same, of course, can manifestly be said of Prince Philip; and our prayers and thoughts are very much with him this morning.
"To declare a lifelong dedication is to take a huge risk, to embark on a costly venture. But it is also to respond to the promise of a vision that brings joy."
The Queen's most famous declaration of her commitment to service was made during a visit to South Africa, on her 21st birthday - April 21 - when she vowed to serve the Commonwealth.
Princess Elizabeth, as she was then, said: "I declare before you all that my whole life, whether it be long or short, shall be devoted to your service and the service of our great imperial family to which we all belong."
Dr Williams said: "But we are marking today the anniversary of one historic and very public act of dedication - a dedication that has endured faithfully, calmly and generously through most of the adult lives of most of us here.
"We are marking six decades of living proof that public service is possible and that it is a place where happiness can be found."
He went on to say: "This year has already seen a variety of Jubilee creations and projects.
"But its most lasting memorial would be the rebirth of an energetic, generous spirit of dedication to the common good and the public service, the rebirth of a recognition that we live less than human lives if we think just of our own individual good."
Take a look at pictures from Tuesday's Diamond Jubilee celebrations below: