There’s a fair bit of electricity crackling in the air of the old converted engine shed in North London. Whilst September is seeing a vast plethora of star studded musicians grace these hallowed circular walls for the annual iTunes Festival, it is arguable that none are of quite such a totemic presence as Robert Plant.

In fact, despite the fact that the man attempts to belie this by arriving onstage modestly amongst the cluster of his six-piece band (known collectively as ‘The Sensational Space Shifters’), he resembles something of an artefact from a bygone age. Craggy of face, but with that iconic lion’s mane of hair in place, it is as though we’re seeing a museum piece in our presence or a rock music equivalent of an etching from Mount Rushmore brought to life.

To Plant’s credit, it would do him an unholy injustice to consign his standing to that of the past. He is someone who has always marched to the beat of his own drum. Keen to distance himself from the cries from public and former band mates alike for a subsequent tour to the 2007 O2 Led Zeppelin one-off reunion show, he continues to forage down musical paths that others of his stature wouldn’t dare venture.

Always seeking, always searching, his musical magpie leanings – which have been there from day dot; after all, the early foundations of Led Zep focused on lifting blues from the 30s and bringing them forward – have fared him well.Publicly, he has stated that it was his experiences recording with Alison Krauss on 2007’s surprise commercial success Raising Sandthat led to him becoming a better singer. Intertwining with her vocals, he learnt to master the measure of restraint. Subsequent records, Band of Joy and the new Lullaby and….The Ceaseless Roar have built upon this success with aplomb.

It is from this latest album that Plant chooses to open up his set. ‘Turn it Up’ is a slow burn; its fidgety verse melody taking up space until a stomping and jagged guitar punctuation greets the chorus. It reminds one of Page and Plant’s No Quarter project from 1994 and it lays the foundations for the set nicely.

Next comes the first big surprise of the evening. The sweet chiming chords of ‘Thank You’ from Led Zep II emit from the stage. The crowd, uncertain if this is quite what they think it is, welcome the song with loud cheers once the Hammond organ break arrives and Plant’s bare, vulnerable vocal takes centre stage.

As the song travels into higher gears towards its conclusion, Plant surveys the stage with the microphone stand cusped in both hands, tilted like the days of old. During the rockier moments of his whole set, his face will pucker up to express the intangible, but primal, testosterone that is buried innately within rock music.

We are soon spoilt further with a ‘Black Dog’ reworked. The ubiquitous guitar riff is displaced in favour of some slide guitar and world flavour. Drums shuffle as its backbeat and the punchy seesaw of the vocal line sits atop the music like an expensive gin poured over ice. It’s rather lovely.

The mix of free, lax world melodies with primordial thumps is a compelling concoction throughout the night. All the while, Robert Plant is somehow recognisably the man of his youth but with more grace and less fire. People might come to gawp, stop and stare; to see a fading king before he passes on, or to wallow in reminisces and vicarious nostalgia for what most never had but cherish all the same. They don’t get that. Like all true artists, this one is pushing forward, compelled by the voyage and the journey that makes any art lover love their artists.

He sprinkles in new material here and there, never forgetting that the ebb and flow of a good festival set is to anchor each gesture of the new with a dash of the old. Whilst we get new single ‘Rainbow’ (as Plant introduces it as ‘What they used to call a single… not a bad state of being… a 7 inch single’), we also get ‘Going to California’, replete with the mandolin contorting beautifully around the acoustic guitar.

‘Babe, I’m Gonna Leave You’ is completely and utterly spine tingling. For the stoic, unmoved members of the crowd – a de facto staple of any festival attendance – this is the turning point. Thank God for that. To have remained unmoved would have garnered a call to the emergency services for fear of a lack of pulse. Instead, en masse, the crowd, who have been lubricated with the sweet nectar of solid song writing throughout the set, become suitably intoxicated. They loosen up. The cheers get louder.

An electric, raucous and elongated cover of Bukka White’s ‘Fixin To Die’ follows. It sets up a thunderous climax.

When it duly arrives, ‘Whole Lotta Love’ is so damn powerful, you would be forgiven for thinking that the pillars of the Roundhouse may well crumble and fall to rubble. It’s like the sound of the apocalypse, and it is in this moment that the mild(er) mannered Robert Plant is gone and in its place the feral, wild Plant of old is there in a flash.

No matter how much you might prepare yourself for hearing that staple and no matter how impressive it sounds on YouTube, vinyl, Spotify or elsewhere, nothing can quite match the ferocity of hearing it in the flesh. It is hard to find the words to do it any sort of justice. Breathtaking. The band duly exit the stage.

With the crowd baying for more, the group re-emerge with the bold decision of playing a one-song encore that consists of a new song off of a newly released album. In this case, it is the catchy strut of ‘Little Maggie’. It turns out to be a fine ending. And with that they’re gone.

The Levee didn’t break tonight, but the Roundhouse almost did. An incredible journey and an incredible gig. Follow that, iTunes Festival.

Photos by iTunes Festival, London.

The iTunes Festival continues throughout the month of September. Keep posted to SupaJam for all the reviews and news on this musical feast.