It probably says something about the transience of modern pop that a band like Bloc Party can disappear for a mere four years and yet already be entitled to an emotional ‘reunion’, but try pontificating on such matters to the hordes of excitable disciples lined up to see their gods at Koko tonight and you’ll likely get nowhere. I speak to one who’s ditched work (in Brussels) to be here, a pair of Australians who’ve paid double face value to see them, and a group of students who declare through a boozy haze that they’d "kill for Russell Lissack". Someone also tells me Bloc Party got them into exercise. Of course.

Even if Bloc Party have made a fair few fumbles (mostly lyrical, occasionally genre mismatches) while trying to outrun the sound of Silent Alarm, tonight’s fanclub gig-goers quite obviously didn’t lose the faith; indeed, a quick straw poll finds a surprising dead split between people who name the debut, Weekend In The City and Intimacy as their favourite records, nicely undermining my own narrative about them running on empty before the hiatus. Clearly, they continue to make a whole bunch of people freak out and inspire a particular brand of obsessiveness. You can’t argue with that.

With a new album Four on the way in August, Bloc Party announce their return with a smattering of new tracks and euphorically-received oldies. Opener ‘3x3’ is pretty much the Bloc Party you’d expect (interlocking guitars, yelps, a line of "no one loves you"), while second new track of the night ‘Kettling’ offers a particularly heavy take on the double-guitar attack and sees the welcome return of secret weapon bassist Gordon Moakes to backing vocal duties. Intimacy cut ‘Mercury’ is received like a pop classic, the crowd filling in the vocal loops, letting frontman Kele Okereke take a smiling backseat, followed by ‘Hunting for Witches’, probably the only singalong song yet written which incorporates the phrase "reasonable thought". Funky new cut ‘Real Talk’ takes things down a peg, a slightly maudlin, understated number that peaks with a beautiful bit of falsetto and a typically earnest Kele plea to "let your heart rest on mine".

Kele’s time as a solo artist may have divided critics, but it’s clearly done the man himself a whole lot of good. Where once a nervous twenty-something said very little, he now straddles the stage, toys with the crowd and even confidently slips in a bit of solo single ‘Tenderoni’ in place of the intro to ‘Song for Clay’. Likewise, the band bounces off each other, any of the rumored tension that had built up around ‘Intimacy’ apparently long laid to rest as they power through ‘Banquet’, which as expected, causes a big chunk of the crowd to lose their voices. There’s a more-than-polite clap-along for spiky new one ‘Team A’, a cut that pegs ‘Four’ as a firmly guitar-led record, full of the band's trademark left-turns. Tacky Intimacy bonus track ‘One More Chance’ gets a rave reception, while there’s a nod to fan favourite ‘Skeleton’ before ‘Helicopter’ sends pints and gangly teenagers flying.

The encore offers up the most melodic, single-worthy new track, called ‘Truth’, whose mid-tempo sweetness recalls ‘So Here We Are’ and ‘Two More Years’. ‘This Modern Love’ reduces functioning human beings to crying wadges of jelly, followed by a hearty ‘Happy Birthday’ to bassist Moakes and a chance for, as Kele puts it, the crowd to show its ‘got a little bit of fight left’ with a brattish ‘Ares’. Before rounding the first chunk of the set off with Rihanna’s ‘We Found Love’ fused with dance-off ‘Flux’, a beaming Kele says, without a trace of sarcasm, "thanks for showing us you still care".

Realistically, of course, a fan club audience was always going to care, and the real test of the new stuff will undoubtedly be the record’s release: have they over-produced the life out of it? Is Kele singing about Sudoku again? Does Matt Tong actually get to play the drums? Tonight, though, they were unimpeachable. Shuffling back on just as everyone’s leaving to turn most of the crowd into 90% sweat with a second encore of ‘Like Eating Glass’, Bloc Party close the night with a flourish. No doubt those who’ve always seen these four blokes as too teenage, too earnest, too tuneless and even too conservative will be sharpening their knives for the band’s August comeback, but tonight Bloc Party announce their return by doing what they do best and what few bands ever actually achieve: mattering to a lot of people.

Bloc Party at Koko setlist

'3x3'
'Kettling'
'Mercury'
'Hunting for Witches'
'Real Talk'
'Octopus'
'Tenderoni / Song for Clay'
'Banquet'
'Team A'
'One More Chance'
'The Prayer'
'Helicopter'

'Truth'
'Ares'
'Happy Birthday'
'This Modern Love'
'We Found Love / Flux'

'Like Eating Glass'