There comes a point in Smashing Pumpkins’ 30th anniversary show when any rational person might think enough really is enough. That point is when the band tick over into their third hour on stage by embarking on a faithful rendition of Stairway to Heaven while what appears to be a woodland throne decorated with fairy lights makes its way from one side of the audience to the other. What next? A version of Moby Dick with an actual whale brought out from backstage?

Never short on self-importance ... Billy Corgan of Smashing Pumpkins. Photograph: Burak Cingi/Redferns

That this doesn’t serve as a salutary lesson in the perils of excess is testimony to the depth and breadth of Smashing Pumpkins’ catalogue. Despite their initial association with grunge, they were never one-dimensional shouters, and the best moments tonight come with their drifts towards tightly constructed AOR, on 1979 and the sublime Try Try Try, or where droning guitars mesh high and low notes, on Rhinoceros or Drown. Billy Corgan has a facility with melody and an interest in tone and texture that is miles ahead of most of his alt-rock contemporaries.

Yet this first visit to the UK since guitarist James Iha and drummer Jimmy Chamberlin rejoined hasn’t quite filled Wembley Arena – there are patches of empty seats – which leads one to wonder why this band, whose take on a fairly limited formula is so inventive, don’t have the pulling power of the much more workaday Pearl Jam.

Perhaps that’s down to Corgan, whose press persona and sense of style have always suggested the kind of man who might file his teeth into fangs in order to open the most intimidating occult shop in Nuneaton. He’s never been short on self-importance and he rolls it out for us tonight: there’s a fabulously pretentious prerecorded speech played on a big screen, a cover of Space Oddity that Corgan performs, wearing a hooded cloak, on top of a podium behind the drum riser, and a couple of songs on which he seems to be playing piano on a pulpit. It’s barking, but in a thoroughly entertaining way.

Three hours, truthfully, is more than enough. But a show that might have scared the faint of heart turns out to be a bit of a treat.