Four days of events began on Thursday when a happy-looking Elizabeth waved to crowds from the balcony of Buckingham Palace after a military parade and Royal Air Force flypast, and later led the lighting of the Principal Platinum Jubilee Beacon at her Windsor Castle home.
More than 1500 beacons were lit across the United Kingdom, Channel Islands, Isle of Man and overseas UK territories to form a "chain of lights". Fifty-four beacons were also lit in capital cities across the Commonwealth.
Thursday marked not only the start of the Jubilee, but also the 69th anniversary of the coronation of Elizabeth, who became Queen on the death of her father George VI in February 1952.
The 96-year-old has now been on the throne for longer than any of her predecessors in 1000 years, and is the third-longest reigning monarch ever of a sovereign state. Opinion polls show she remains hugely popular and respected among British people.
The beacon, which came on the last supply ship to the Pitcairn islands six weeks ago, will be lit during a dinner everyone will most likely attend and contribute to, said Colin Leeman, administrator of the British Overseas Territory.
"This is what the community does to celebrate the significant events - they see a close relationship with the British Crown," Leeman told Reuters. To mark the occasion the island's generator, which powers all of Pitcairn and normally turns off at 9.15pm, will run for an extra hour or so to allow for more festivities.
The British colony is mostly populated by descendants of crew from the ship the Bounty, who settled there with Tahitian wives after a legendary 18th century mutiny on the high seas.
The rocky outcrop, 5500km from New Zealand, hosted the late Prince Philip in 1971 when he sailed the royal yacht across the Pacific.
Leeman said that dessert at the celebration would be a Pitcairn take on the Platinum Jubilee Trifle.
Canned mandarins were substituted for fresh local citrus, the amaretto substituted for vanilla in the biscuits (which Leeman was responsible for baking and had burnt twice). Leeman said the island was a little short on cream and had no white chocolate.
Charlene Warren, the islands' mayor, said she had written a short speech and expected some singing.
"She is our Queen, and so it's actually an honour to be able to celebrate her life," Warren said.
The island also has plans to plant a tree as part of the Queen's Green Canopy environmental initiative - a coconut, a palm or a breadfruit tree.
