What seems both hilarious and logical in the light of day takes on a different complexion when the alarm goes off at 3am and you cannot remember why you are in a Travelodge. Then it came back to me: the first night of Antony Gormley’s alleged artwork, One and Other.

And one of the Others is my middle brother, Patrick, allocated the fourth plinth in Trafalgar Square from 4 till 5am. It seemed necessary to address the pressing question: is my little brother “art”? I got up, shuddering.

It was partly my fault anyway. When the pleasingly ridiculous idea first invited online applications, I virtually forced my whole extended family, down to the youngest nephew, to put their names down. Gormley wants a random cross-section of us for his computer to pick? Well, we are as random as any. I then forgot all about it until Patrick — Lincolnshire solicitor, pipe smoker, folksinger, the living antithesis of all things cool and Brit Art — triumphantly informed me that from 4 to 5am on the first day he would be up there. In his morris dancing costume, hat and bells. Playing the melodeon.

So I got out of bed and walked through the dark city: down St Martin’s Lane with the lights off over Chicago and Calendar Girls; past Stringfellows, where the last-shift bouncers yawned; past ragged sleepers and a lone street cleaner and scavenging, squawking seagulls.

After the media scrum of the daytime, with cameras surrounding earnest demonstrators and bashful exhibitionists, after the TV correspondent sneering, “This is art for the Facebook generation,” it felt different.

In the weird loneliness of the early hours, the enterprise began to feel artistic for the first time; quixotic, strange, subversive. Patrick even had a message. His message is that there ought to be morris dancing in the Olympics opening ceremony as well as hip-hop.

Dawn seemed far off. In the dark square, Patrick was sitting on the fountain side being filmed by Look North and making unsettling deadpan jokes. (He does this. When an anxious member of the One and Other team rang him to check he was coming, he cheerily said, “Yes, that’s right — Trafalgar Square in Liverpool, isn’t it?”) His wife Judy looked on. His daughter Helen muttered: “Next time one of our family is on a national monument, could it be in a less embarrassing outfit?”

“Fatherhood,” said Patrick, “is very much about embarrassing your children. I am good at it.” In his defence, let me say that he also plays the pipes, and once did a set with the Chieftains at the Albert Hall.

Helen filmed him on her mini-camera, only to be accosted by a “heritage warden” telling her she needed a permit from the GLA.

“You’re telling me that this huge bit of publicly funded art, the open plinth for all, needs a permit? At three in the morning?” We rejoiced at the Britishness of it. Though an even better example had gone before: Patrick, as bagman to the Alford Morris, had to ask formal consent of the Westminster Morris to play on their patch. He got this, in a weird exchange of e-mails ending “Wassail!” But his invitation to London morris men to dance at dawn met with a zero turnout. Load of pantywaists!

Helen, Judy and I were up for the odd whirl, although our efforts to involve the police leaning on the balustrade were met with cold stares. We had slightly better luck with the heritage warden, who did eventually tap his foot a few times. Perhaps he was aware that Lord Redesdale’s heroic amendment in the Lords had, in the last minutes of the Licensing Act of 2004, created a blanket exemption for morris dancing. They can kick up their belled heels anywhere without reprisal.

At four, hefting his melodeon, Patrick reported to the Portakabin office and was loaded on to the JCB that raises Plinthians aloft. The woman before him had expressed her art by taking off one garment every minute, and was now down to modest shorts and vest. They swapped places and Patrick yelled across the square, “This is for the thousands who play and dance the morris, with no thought of profit or celebrity.” And began.

There’s something about music, even on a melodeon, that changes everything. It floated across the square, and the weary night shift in the Portakabin wandered out to watch and smile. “Can he keep it up for an hour?” asked one, and I reassured him that nothing but closing time has ever been known to stop him. The old tunes echoed off the stately facades: Lads a’Bunchum, Hunt the Squirrel, The Nutting Girl and, for Nelson on his column, a sea song: The Bold Princess Royal. Two scantily clad girls and a wandering group of lads stopped, for longer than they had meant to, and looked up at the absurd, triumphant figure in the reddening morning clouds.

I felt the shivering Sky Arts team needed encouragement, and yelled, “Play Waltzing Matilda for Rupert Murdoch!” So he did. With bits of metal replacing large parts of his legs (because of a long-ago motorbike accident) our hero stood his ground and defied his vertigo. (“The top,” he later shuddered, “is smaller than you think. And wobblier. They’ve put planks on it, and they bounce.”) But he did it. Like the Piper at the Gates of Dawn he brought up the light: whiter clouds scudded past Nelson as Patrick played on high above us until the JCB came to lift him off. The next Plinthian was a girl in a filmy white dress who said, “I am going to do a yogic salute to the Sun and write positive affirmations on paper birds and pin them to my dress.” After her, already lined up in the Portakabin, a gruff man saying “Not sure what I’ll do. I may put on this cow costume.”

So was my brother a piece of art? Actually, I think so. He subverted the hip Gormley subversion. He defied fashion. He is not from the Facebook generation, he did not want to promote a PC charity or reassure himself he existed. He loves the music, loves the morris and has put hours into learning the craft since he taught himself by ear at 17. Like all proper artists, he doesn't give a damn about the mockery and will stay up all night, even if nobody is watching. Yep, it was art all right.

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