Midway through her set, Madonna inserts a mini-tribute to Michael Jackson into her rendition of Holiday. It's appropriate, but not just because of Jackson's recent demise. Born just 13 days apart, the careers of pop's two biggest megastars have always seemed to exist in parallel to each other. But while the last 15 years of Jackson's life saw him slowly waste away, Madonna has spent the same period intent on solidifying her own immortality. This scrappy hunger has been the one constant in a career marked by endless reinvention, a quality which has always been beneficial to her, but having reaffirmed her place at the head of the table several times over, a sense of purposelessness is beginning to creep into it.
Tonight's show finds her emphasising her strength and power above all else. Madonna comes across not so much as the Queen of Pop, but its Iron Lady, intent on bending it to her will. She summons up specially recorded video images of younger superstars – Kanye West, Britney Spears, Justin Timberlake – with a snap of her fingers. The choreography is designed to display how limber she is. It is undoubtedly impressive on occasion: during the show's centrepiece, She's Not Me, Madonna abuses four immobile dancer mannequins – ripping wedding veils from their heads, French kissing them, finally strangling one – in a compelling display of alpha female superiority.
But this also has an increasing tendency to manifest itself in tiresome ways. There's no reason why a 50-year-old shouldn't flaunt her gym-sculpted body or express her sexuality; what disappoints is the mundanity of how she does it. Cutesy cheerleader skirts, vague S&M signifiers and choreographed pole-dancing are far from transgressive, especially from a woman who has been genuinely bold in pushing sexual boundaries. Elsewhere, a montage of senselessly arranged "humanitarian" images, from Iranian rebels to Mother Teresa, elicits groans from the audience.
Trying to prove her youthfulness, trendiness and good heart are goals which should be beneath Madonna. She has a back catalogue like no other, and it serves her well enough to redeem tonight's show. A rave version of Like a Prayer, mixed into Felix's Don't You Want Me, is electrifying, the kind of thrilling live moment that few others could match; there's a brilliant perversity in reimagining the bubblegum Dress You Up as a metal guitar-fest.
These are reminders that Madonna is not a woman to be written off, but they also highlight the paucity of interesting ideas elsewhere. Madonna's undisguised questing for immortality comes off as an empty pursuit because she has already achieved it – a fact that her own Jackson tribute should have made clear to her.
At MEN Arena, Manchester, tomorrow. Details: madonna.com
