Queen Elizabeth II renewed her vow to serve on Monday as she made a deliberately low-key start to five months of diamond jubilee celebrations marking her 60 years on the throne.
Six decades since the sudden death of her father King George VI on February 1952 made the young princess a queen overnight, the monarch said in a message to her subjects that she wanted to "dedicate myself anew to your service".
The 85-year-old also thanked the nation for "the wonderful support and encouragement that you have given to me and Prince Philip over these years," a reference to her husband of 64 years, the Duke of Edinburgh.
In contrast to the lavish celebrations planned for the official jubilee in June, Monday's anniversary will be largely business as usual for the queen as a mark of respect for her beloved "Papa".
She has two engagements in Norfolk in eastern England, including a visit to the town hall in King's Lynn and to a nearby school.
In King's Lynn, a few dozen wellwishers had already gathered in freezing conditions an hour before the queen was due to arrive, while council workers cleared snow from around the building from which a Union Jack flapped in the wind.
Among the wellwishers was Colin Edwards, 71, who had made the long journey from Ruthin in North Wales for the special day.
He said: "We couldn't miss the chance of seeing her on the 60th anniversary of her accession. I have got a special poem I have composed to present to her.
"She is absolutely amazing, she is warm, gracious and dedicated to her job. She is an inspiration."
The queen's programme over the coming months will be restricted to Britain, but other members of the royal family will criss-cross the Commonwealth in her place, from Canada and Australia to tiny Tuvalu in the Pacific.
The celebrations will culminate in a four-day public holiday on June 2-5, the highlight of which will be a flotilla of 1,000 boats sailing up the River Thames on June 3.
On Sunday, the queen braved snowy weather to attend a church service on her Sandringham estate alongside her 90-year-old husband, who appeared sprightly despite undergoing heart surgery just before Christmas.
On the fateful day in 1952, the 25-year-old Elizabeth was on a visit to Kenya when she received the news from her husband that her father had passed away in his sleep.
As she returned to Britain, she was greeted at the airport by prime minister Winston Churchill and the enormity of the challenge would have dawned on her.
Her coronation, a solemn affair, did not take place for more than a year, on June 2, 1953.
In the message to her subjects, the queen said she and Philip had been "deeply moved" at all the kind messages marking the jubilee.
She reflected on the importance of family and friendship, and urged her subjects "to look forward to the future with a clear head and a warm heart".
Prime Minister David Cameron said the queen had guided the country "with experience, dignity and quiet authority" -- and he dismissed suggestions she was "simply a glittering ornament".
"That misunderstands our constitution and it underestimates our Queen. Always dedicated, always resolute and always respected, she is a source of wisdom and continuity," he said.
"All my life, and for the lives of most people in this country, she has always been there for us."
One member of the royal family who will be absent from the early stages of the jubilee celebrations is Prince William, who last week started a six-week mission as a Royal Air Force search and rescue pilot in the Falkland Islands.
Argentina, which claims the islands in the South Atlantic, is furious at the prince's posting.
However, the second in line to the throne will then join family members in touring the globe, taking his wife Catherine to the Asia-Pacific region, while his father Prince Charles visits Australia and Canada.