Tonight is the second night of Wilson's week-long summer residency at The Royal Festival Hall, and the show is split into two distinct sets – the centrepiece 'SMiLE' being braced either side by two greatest hits packages. As the black veil drops, we are greeted with an image of friends around the campfire. Wilson sits in the middle, a fairly large man with a swish of silver hair and a childlike grin, surrounded on either side by The Wondermints – his Californian backing band - and an assortment of other musicians that make up his 18-piece pop orchestra. As the tunes begin to roll, their closeness on stage becomes vital. An absolutely heart-wrenching ‘Surfer Girl’ is played with a sublime sensitivity and sung with such an intense passion that it’s a wonder there’s a dry eye in the house. The harmonies are as precise and enchanting as you’d expect; The Beach Boys' killer vocal lines being re-created beautifully throughout. The gorgeous ‘In My Room’ follows, and ‘Please Let Me Wonder’ is added to a loving selection of early ballads. The full band now in swing, we are treated to a watertight version of ‘California Girls’, followed closely by a celestial ‘God Only Knows’. It sounds as wonderful as the record and it is, by all accounts, magnificent - Wilson making his strange chest patting gestures throughout the song's sonically stunning coda. Whether the man is ‘all there’ or not is debatable, but his singing voice is - for the most part - intact and not a note seems to falter. However, inbetween his vocal parts he seems to slump: a fixed gaze on his face, devoid of any emotion, suddenly flickering back into action with a wide smile across his face, the keyboard in front of him barely touched. It is a strange site to behold, but one that does not detract from the timeless quality of these songs. The new songs taken from this year’s ‘Getting In Over My Head’ still get a rapturous response and stand up well against Beach Boys classics. It’s great to see that after years of turmoil the ability to create brilliant harmonic variations and catchy melodies haven’t completely deserted a man who has been labelled ‘a genius’ on more than one occasion.

After a short interval, the band/ensemble/orchestra take the stage once again. This is what we’ve all been waiting for: ’SMiLE’. Although many of the songs intended for the ’SMiLE’ album have been re-jigged and released on other Beach Boys records, they have never been put together in this order and with Van Dyke Park's original lyrics fully intact. The outstanding a cappella intro that is ‘Our Prayer’ signifies the beginning. From then on it is a 45-minute trek through some of the most intense musical landscapes you are ever likely to encounter. Piano-driven ballads switch to fast, brass-punched sections that spiral, contort and explode with such regularity that, within the first ten minutes, we have been taken from our seats and plunged straight into the depths of Wilson’s mind. The heraldry of ‘Heroes & Villains’ is replaced by the crazed rock 'n' roll of ‘Do You Dig Worms’ – the musicians effortlessly swapping instruments, all playing this masterpiece with technical prowess and loving devotion. Rather than an album ‘playback’ of tracks, the 'SMiLE' section is split into three 15-minute suites. Wilson called it his ‘Teenage symphony to God’, and with the themes of lost virginity (’Wonderful’), nostalgic Americana (’Cabinessence’) and the benefits of the natural (’Vega-tables’) layered amongst a number of other reprises and rejuvenations, the man who once played his piano in a sandbox wasn’t too far off the mark. Having burrowed further down the rabbit hole, the insanity of this album – they use tools at one point and the string section dons fire helmets – is apparent, yet entirely captivating. It is an extravaganza of joyous confusion; re-constructed with enough passion and dedication that Wilson’s mastery of all things melodic and inventive is once again, 37 years after its troubled conception, erupting for all to see. Its closing moment: an exhilarating ‘Good Vibrations’. Now restored to its intended length, Wilson revels in telling the crowd to “Get Up!”; everyone does exactly as he says, not sitting down until the encores of ‘Fun Fun Fun’, ‘I Get Around’, ‘Barbara Ann’, and ‘Help Me Rhonda’ have sent them into a frenzy. A surprisingly simple ‘Love & Mercy’ closes proceedings, and after almost three hours the assembled thousands are left blown away.

The last 45 minutes of Beach Boys classics were fantastic, with Wilson continuing to swing his arms around, sporadically unaware of his surroundings but managing to pull off his vocal lines with strength and enjoyment. However, ‘SMiLE’ was the undoubted highlight - the arrangements perfectly bubble-wrapping Wilson's intricate melodies and sun-hazed vision. Tonight was not only the unveiling of an album that has laid in ruin for the best part of half a century, but also a complete celebration of the genius behind its creation.