Queen relaxes with gin after formal duties
Clutching a tumbler of gin and Dubonnet with a slice of lemon and three ice cubes, the Queen, black handbag perched on her left forearm, worked the room as she has so many times before.
Moments earlier she had been guided to the Royal Gallery in the Palace of Westminster by Commons Speaker John Bercow and the Lord Great Chamberlain, the Marquis of Cholmondeley, for a drinks reception.
With the loyal addresses and the formal part of the morning finished, it was time for her to relax and enjoy herself in ornate surroundings.
Two paintings from 19th century artist Daniel Maclise dominate the Gallery's flanks, one depicting the aftermath of the Battle of Waterloo and the second Nelson's death at Trafalgar.
Beneath the great works and portraits of her predecessors on the United Kingdom's throne, the Queen surveyed the hundreds of MPs and peers gathered to receive her and mark her 60 years on the throne.
Labour leader Ed Miliband was a last-minute arrival to the impressive room, searching for the door keeper holding the sign reading Group 3 and 4, a group in which he was supposed to be that very moment.
"Mr Miliband, Mr Miliband," called the Commons official to no avail, so in stepped shadow Olympics minister Tessa Jowell to rescue her lost leader, adopting a football terrace boom to bellow: "Ed! Ed!"
Ms Jowell and fellow party big beasts Keith Vaz, Sadiq Khan and Peter Hain immediately formed a protective ring around Mr Miliband, who later beamed that today was a "wonderful, memorable occasion" for people to "pay tribute to the extraordinary service of Her Majesty".
He gushed: "We saw the huge affection, gratitude and admiration for her expressed by the reaction to her speech.
"Everybody here will remember this occasion for the rest of their lives."
But if the leader of Her Majesty's Loyal Opposition was cutting it fine for his date with royalty, Prime Minister David Cameron very nearly missed his slot altogether.
He appeared in the disorganised line-up red-faced, breathless and gently perspiring, but still bowed low as the Queen offered her hand.
With the Government's health reforms returning to the Commons today, perhaps his mind was temporarily and understandably elsewhere.
The Queen saved her seemingly most genuine of smiles for her fellow octogenarian, Father of the House Sir Peter Tapsell, who was first elected to Parliament 55 years ago.
When the Queen left the group of Conservative grandees, Mr Cameron was quickly handed a glass of chilled Champagne and began guzzling, his left hand resting in his trouser pocket as he relaxed and chatted with Foreign Secretary William Hague.
The Queen carried on, surrendering softly spoken words to her subjects and smiling graciously as they offered platitudes.
Former energy secretary Chris Huhne, who quit the Cabinet after being charged with perverting the course of justice over allegedly passing speeding points to his ex-wife Vicky Price, smiled and laughed as he enjoyed the free bubbles being passed around.
He appeared not to have a care in the world, despite facing a theoretical life sentence if he is found guilty of the offence, which he denies.
Mr Bercow was today at his most attentive, rarely leaving the Queen's side, revelling in his ceremonial role, flashing small grins at his allies and larger smiles at his foes.
He was particularly keen for the monarch to meet modernisers in the shadow Cabinet including Caroline Flint (energy), Chuka Umunna (business) and Yvette Cooper (home affairs), who is tipped as a future Labour leader and, perhaps one day, Britain's second woman prime minister.
There was a quick reprimand from a Lords official for Labour MP Geraint Davies who, in breach not just of protocol but also Parliamentary rules, held aloft his iPhone in an attempt to snatch a picture of the Queen as she passed by, presumably fearing he would get no closer.
The flustered Swansea MP need not have worried as he was introduced to the sovereign some 20 minutes later, though with time to spare he perhaps should have practised his bow.
The Queen, serenaded by an eight-piece mini-orchestra, was at her most animated during the 40-minute mingle when she became involved in a deep discussion with Labour MP for Stoke on Trent, historian Tristram Hunt.
Could Mr Hunt really be telling the ruler why he believes a new state started today would never accept a monarchical system, a theory about which he spoke at length on the floor of the House just two weeks ago?
"We were discussing the Minton tiles on the floor of the Royal Gallery, which were made in the Minton factory in Stoke," he explained.
"She was fascinated by them, and it meant I was able to plug my constituency."
One of today's trickiest meetings for Her Majesty could have been with the outgoing Archbishop of Canterbury, Rowan Williams, who last week declared he would quit the post at the end of the year.
A sombre Dr Williams refused to divulge the contents of his audience with the Queen, but admitted they had discussed his decision.
He described today's occasion as "wonderful" and praised "three excellent speeches".
However, the Archbishop of York, John Sentamu, tipped to succeed Dr Williams, was altogether more flamboyant, laughing and joking with the Duke of Edinburgh before the Queen arrived to share their mirth.
"It was a wonderful joke, but this particular joke is so special it will go with me to the grave," teased the cleric.
He confided that he and Tory Party chairwoman Baroness Sayeeda Warsi initiated a standing ovation for the Queen on their side of Westminster Hall, hailing the "heartfelt thanksgiving" offered by peers and MPs for her six-decade reign.
Meanwhile, officials held their breath as Prince Philip and Baroness Trumpington, the 89-year-old peer who hit the headlines last year when she flicked a colleague a V-sign while sitting on the red benches, entered into debate.
What politically incorrect observations might the duo be exchanging?
When asked, Baroness Trumpington was typically forthright: "We were sharing a joke which is none of your business."
And then with politicians suitably refreshed pre-lunch and facing another Commons debate on the NHS while the Lords scrutinise justice reforms, it was time for proceedings to draw to a close - a chance for Mr Bercow to resume centre stage.
"Three cheers for Her Majesty The Queen!" he cried, with guests answering the demand.
And with that the Queen turned away, perhaps thinking of her return to the Palace of Westminster in six weeks when she opens the new session of her Parliament on May 9 - and will meet all these peers and MPs once again.