Having torn myself away from the epic ding dong that was Donegal v Monaghan – I can’t help feeling that yours truly branding them “invincible” in the current Hot Press contributed to the latter’s downfall – I arrive in sunny Rathfarnham in time to see London Grammar demonstrate in the Heineken Live Project tent why there’s such an insane cross-channel buzz about them at the moment. Imagine The xx fronted by Florence Welch and you’ll have some idea of the moodily atmospheric noise this trio make. A real star in the making, singer Hannah Reid is at her histrionic best on recent single ‘Wasting My Young Years’, which also strays into Lana Del Rey territory.

A quick flit to the Main Stage reveals Mark Lanegan to be as ditchwater dull live as ever. No one’s asking him to turn into Bruce Springsteen, but a little crowd interaction would be nice. Stripped of any kind of showmanship, grunge-y gems like ‘The Gravedigger’s Song’ and ‘Methamphetamine Blues’ mainly fall on deaf ears.

Today is my first live sighting of Sohn, the Vienna-based producer and multi-instrumentalist who proves to be the missing link between Perfume Genius and Massive Attack. Warm waves of synth, insane distorted loops and those impassioned Mike Hadreas-like vocals combine to produce something really rather special.

The Clarkian stuff is also comprehensively strutted in the Live Project tent to Flume, the hotshot Aussie producer who’s recently got his fader fingers on Disclosure. The prog rock liquid wheel visuals are the perfect accompaniment to such squelchy acid delights as ‘Sleepless’.

“I had a crazy good time,” he says afterwards. So did we.

Back on the Main Stage, the reaction to Hot Chip is merely polite until they unleash the poptronica double whammy of ‘Over And Over’ and ‘Ready For The Floor’. Five albums in and sad to say their quirky Pet Shop Boys shtick is starting to wear decidedly thin.

Rocking a look that’s best described as “hipster Su Pollard”, Karen O finally brings some genuine star talent to the Main Stage. From slowburning start (‘Sacrilege’) to kick out the jams finish (‘Heads Will Roll’), the Yeah Yeah Yeahs are the de facto headliners that the vast majority of the 10,000 punters have come to see.

In between the crowd-pleasing likes of ‘Gold Lion’, ‘Zero’, ‘Maps’ and ‘Pin’, there’s also time for Ms. Orzolek to sing ‘Happy Birthday’ to an embarrassed looking crew member.

While a highlight for this particular old man, it’s fair to say that the vast majority of Longitude-goers know little and care even less of Kraftwerk regardless of how many dimensions they’re in this evening.

“They’re just four DJ blokes standing there doing fuck all,” is the verdict of one floppy-fringed teen who’s lucky to escape a corrective Clarkian slap. People standing at the back of the arena tell me afterwards that they were barely discernible, but up close the 3D graphics are as stunning as the music they accompany. Ralf’s Man Machine-era arm appears to reach out into the audience during the opening ‘We Are The Robots’; the ‘Trans Europe Express’ similarly threatens a high-speed collision with the front-rows and it’s floating nuclear hazard signs a-go-go during the technofied ‘Radioactivity’.

Elsewhere, ‘The Model’ is as imperious as ever and ‘Neon Lights’ shimmers like a very shiny thing in the Marlay twilight. Non-believers may have remained unconverted, but none of the Kraftwerk faithful go home feeling anything other than fully sated.

Overall it’s been a fabulous three-days of urban festival-ry, which you can bet on being repeated next year.

STUART CLARK