Plastered to the doors to the auditorium before the show was a sign written by Adams’ own hand. “Do not photograph, record, or use phones during tonight’s performance,” it read.

“Let’s be in this moment together. If you choose to ignore this request, one of our ushers will possibly destroy you and burn your remains in a sacrificial ritual, bringing Ryan the power of Satan.” Some fool in the front ignored it. Adams gave him an earful after the first song.

“Shall I record you? Next time I’ll bring my Blackberry and f***ing film the audience.”

The American has made a name as an awkward customer, a hard-drinking but magical ball of mercurial talent. For five or six songs, 2,000 people held a collective breath broken only by riotous roars of approval in-between.

The singer, clutching his Jamaican flag-coated guitar, cowered beneath his floppy black fringe, swaying on an armless wooden chair he’d specifically requested on his rider. Would he storm off, his temper torch-lit? Was it to be one of those nights?

He slugged on herbal tea.

Poured out some water.

“All I asked for was one simple chair. I’m not like Kiss.

"I don’t need 2kg of make-up.

"I don’t want 16 singing strippers with X-ray guns dressed as nuns. So what do they do? They give me this elf chair. And it’s padded!”

Rescue came, as it often does, with the blues. Adams moved to the piano, and threw his heart into Gold’s fifth track – dropped in key, freer without drums. His voice hovered, on the verge of cracking but never quitewent.

New York, New York was equally special, while upbeats such as Firecracker, selected at random from his black songbook, balanced the tempo.

As the light lifted, Adams joked that the place was like an infirmary, as a passive-aggressive might tease an infatuated lover.

It is easy to forget Adams has poor range, surely only a rhythm guitarist, because his voice has character a thousand lessons cannot buy.

But as the doting admirer overlooks any imperfection, his candid, bleak humour, woven through every lyric, was impossible to resist.

And while there was nothing from his British hit, Love Is Hell, even the ignorant left awestruck.