The celebration, a mega picnic of more than 200 British expatriates, showcased the colourful legacy of the Commonwealth replete with elephant rides, samosas, coronation chicken, British fairy cakes, scones and an element of colonial nostalgia.
The 86-year-old British queen, the titular head of the nation, was crowned after the death of her father, king George VI, in 1952. Over their lives, the queen and her husband Prince Philip have witnessed the transformation of the former imperial empire into a commonwealth of nations and the emergence of a new world order.
Elizabeth II is Britain's second-longest serving monarch after queen Victoria. She celebrated the silver jubilee of her coronation in 1977 and the golden jubilee in 2002.
The jubilee celebration theme in Britain is "street parties and multi-racial bonding", said British High Commissioner James Bevan.
"Today is a people's party day in Britain and we are trying to replicate the spirit of the jubilee party and mood in India. Sixty years ago in 1952, the British society wasn't much heterogeneous. Since then, we have welcomed people from all over the world," Bevan told IANS, describing the changing colour of the British royal events over the decades.
In the last 30 years, the size of the Indian diaspora has grown in Britain and country has nearly one and a half million people of Indian origin, Bevan said.
"The Indian diaspora is one of the biggest, richest and the most successful diapsora in Britain spread across all areas of British life - politics, business and arts. The Indian diaspora is a part of the British society," Bevan said.
He said that 2012 "was a year of events in Britain and all of them were finding resonance in India".
"In April, I hosted the queen's 86th birthday celebrations at my residence in the capital with more than 2,000 Indian guests and we are working with our Indian friends to open the July 2012 London Olympics. We have been running a 'Britain Is Great' in India showcasing the country's past, present and future," Bevan said.
Drawing on the larger picture of exchanges between the two countries, the British envoy said it was a "sign of the widening cultural and people-to-people contact between India, the UK and the rest of the world".
The party, which opened at the British High Commission lawns, brought a slice of the London gala via a gaint television screen, on which was telecast the "Thames Diamond JubileePageant" - a royal party flotilla of 1,000 boats travelling down the Thames in London - live to the audience in the capital.
Central to the tableau was royal yacth HMS Britannia, which was brought back to life for the jubilee after it was decommissioned in 1997.
The ceremonial flotilla that cruised down Hammersmith to Battersea was described by BBC as one of the largest ever. It comprised sail boats, row boats, barges, pleasure vessels, wooden Viking longboats and steam trading vessels. It attempted to recreate a similar river pageant in 1668, recorded by 17th century naval historian and administrator Samuel Pepys in his diaries.
As Queen Elizabeth II stepped into the barge dressed in white, the British viewers in the capital cheered spontaneously. Most of them draped themselves in the colours of the Union Jack.
"The basic idea was to come together and party as would happen in the UK. People came with their own food and watched the Thames Pageant together," Marcus Winsley, head of press at the British High Commission, told IANS.
The food was fusion - reflecting the spirit of the new Britain.
An Indian section hawked "tandoori chicken, grilled spiced potatoes, momos and samosas" while the British High Commission club prepared the special "coronation chicken and scones with cream and jam".
"The Britons here love the Indian 'samosa' because it has the right mix of spices," Winsley said.
The High Commission Charity Fund, which supports Indian charities for under-privilged mothers, children and primary education, set up a confectionary sale corner of home-baked sponge cakes, fairy cakes, scones and Union Jack ginger, donated by the mission's staff.
The celebrations in Britain would continue till Tuesday.