With the pink balloons and pastel-coloured streamers, the Prommers decorated the conductor's podium with a powerful message: "It's a girl!" The girl in question, 56-year-old American Marin Alsop, was the first woman to conduct the Last Night of the Proms in the festival's 119-season history.
She took it in her stride, quipping to the assembled masses, "You sing like natives" after a lusty if wayward delivery of Rule Britannia! with mezzo sensation Joyce DiDonato leading the community singing. Music lovers from all round the world – notably from Afghanistan, China, Japan and Germany – got to their feet waving flags and half-sang, half-yelled, "Britons never never never will be slaves" almost as if they meant it.
Of all Last Nights in recent memory, this was the most enjoyable, the least hysterical and the most warm-hearted. Taking on the tricky end-of-term speech, Alsop showed who was wearing the trousers, in this case her usual discreet black suit with a flash of scarlet at the collar and cuffs.
Alsop praised the BBC Proms as the "ultimate showcase for great artistry and superb audiences". She toasted a new attitude of inclusion in classical music and made almost no response to those of her colleagues last week who "said girls can't do it", praising the support of her parents who gave her that belief from childhood.
Referring to her own orchestras in Baltimore and São Paulo and the outreach programmes she is engaged with, she celebrated the power of music and the importance of it at the heart of our lives. She admired the Prommers for their sharp ears and sensible shoes.
The New York-born Alsop took to the podium with cool confidence, undeterred by the august men who had preceded her, including Sir Henry Wood, founder of the Proms, and the Promenaders' favourite, Sir Malcolm "Flash Harry" Sargent. Before a note had sounded the 6,000-strong crowd erupted in cheers, watched by upwards of 40 million people the world over.
On the same day as Alsop took up these gilded laurels, news leaked that Sir Simon Rattle was tipped to take over as principal conductor of the London Symphony Orchestra when he leaves Berlin in 2017. Although widely expected, it nearly stole Alsop's thunder. Once again, a male conductor was thrust into the limelight, reminding us that no woman has held the top position in one of the world's elite orchestras.
No one at the Albert Hall was in a mood to mind. The Prommers, sporting union jacks in every form from Sikh turban to Viking helmet to knitted tea-cosy, had waited for Alsop's big moment since Roger Wright, the director of the BBC Proms, made his surprise announcement about the Last Night line-up. A woman would be in charge, another would be singing and a third would provide a world premiere opener: the short, glistening Masquerade by American-based British composer Anna Clyne.
In the second half, when traditionally the inflatable bananas, beach balls and bazookas come into their own, flags from all over the world filled the Royal Albert Hall. Prommers of every race and creed, at least 300 of whom were turned away at the door, bobbed and sang but this was, essentially, a Last Night in which the music came first.
This has been another hugely successful season. Average attendance for the main evening Proms in the Royal Albert Hall this year was 93%, equal to last year. A record 57 of 75 concerts in the Royal Albert Hall sold out, six more than in 2012. More than 300,000 people attended concerts at both the Royal Albert Hall and the chamber music venue, Cadogan Hall. Over 8,400 under-18s attended concerts across the season. With standing tickets still priced at only £5 and a season ranging from Wagner's Ring Cycle to Zappa, Urban Classic and Doctor Who, the Proms remain a bargain.
The violinist Nigel Kennedy, kitted out like a chic dustman, played Vaughan Williams's Desert Island Discs favourite, The Lark Ascending. He played with an exquisite mix of grace and favour. Later he returned in a shirt bearing the name of Aston Villa and England striker Gabriel Agbonlahor.
Liverpool had its supporters too when DiDonato sang You'll Never Walk Alone. Alsop led the BBC Symphony Orchestra, Chorus and top soloists in works from Handel to Broadway. She indulged the audience with three tries at Land of Hope and Glory, her beat funkier with every attempt.
DiDonato, the self-styled Yankee Diva, caused gasps when she walked on dressed in a shimmering Vivienne Westwood dress to match her dazzling trills and vocal cascades.
Although she was not in her home state of Kansas any more, Wright had obligingly given her a Toto dog as company for her performance of Over The Rainbow from The Wizard of Oz.
Next year perhaps they could find a woman to conduct the First Night of the Proms. That, as far as I know, would be another first.
