The security is tight in Trafalgar Square. Seven thousand people are packed into half of this historic area in the centre of London. They are here tonight to see a certain well-known Irish four-piece in action. It is probably the smallest audience the band have played to all year.

Hozier is playing from the sound system, as the crowd waits for the arrival of Adam, Bono, Edge and Larry. The set-up has the band positioned right in front of the famous pillar. Nothing wrong with that, but overall, you can see from the off that it is far from an ideal situation. The runway part of the stage is less than 10 meters long. It is going to be hard for Bono to work the audience. Also, there's no big screen behind the band. Which is when you realise: the priority here is to get good television pictures. Highlights will screen on MTV tomorrow night. It is that kind of occasion.

Laura Whitmore – familiar from MTV as well as from the cover of Hot Press – steps forward to do the introductions, carrying it off with characteristic aplomb. And then we are into the music.

U2 open with 'Sunday Bloody Sunday', with the stage lit in red. There is a surge of adrenaline among those familiar with the band's canon. But there is no sense that the audience get it, or the significance of the song, performed in a place like this. The reaction is muted.

Bono dons a tri-colour scarf. "Once upon a time, I wasn't so proud of this flag," he says. "Now I feel so proud." And it is into 'Pride (In the Name of Love)', dedicated to "the military on all sides."

With those familiar landmarks in place, it is time for a taste of Songs of Experience. "Alright, this is something new," Bono announces. "Hope we don't screw it up." They play 'Get Out of Your Own Way' from the new album. To these ears, it sounds great, a fine song from an album that is studded with classic U2 tracks. But the reaction is, again, muffled.

They follow with another new track, 'You're The Best Thing', which is one of the likely stayers from the new record. But still, there is no great sense of excitement and enthusiasm in the audience.

It is strange to see the extent to which a lethargic – and clearly unfamiliar – crowd can affect the sense of occasion. How were they chosen by MTV? Were they given an opportunity to show their interest in U2, rather than in just being there? Judging by the reaction, it seems unlikely. The band play 'Beautiful Day', which remains one of their biggest tracks. U2 are playing well, looking like a team who can stitch the passes together. But the MTV audience seems to be here for all the wrong reasons.

When they drive on into 'Elevation' the crowd begins to respond. That's followed by an equally big rock 'n' roll noise in 'Vertigo'. But the lift-off that might have been anticipated doesn't happen.

The band seem ready to leave the stage, before returning for an encore. "We could save time and not go through the ritual," Bono suggests. He might just be thinking about the fact that Ireland are about to take the field against Denmark in Copenhagen. Then again, he might be surmising that it is better to strike while the iron is still reasonably hot.

"London is the capital of the world," Bono says and you wonder is there a Brexit-related thought somewhere in that fulsome compliment. And then it is into the next-to-final song. Inevitably, it is a lovely and moving rendition of 'One'.

That done, Bono reaches out to Londoners. "There's a noble tradition in this square," he says. Placards are passed out among the crowd. "Make Poverty History". "Bite Back". "It's All Gone South". "Resistance". The crowd wave the placards, as the band play 'Get Out Of Your Own Way' again. It is the most animated the crowd have been all night.

And then U2 are gone, spirited off into the London night.

This was not U2 at their barnstorming best. Neither was the crowd what the occasion might have required. It will, however, look good on TV. That is the biggest win of the night. But as we wend our way out of Trafalgar Square, it is hard to escape the thought that the band are unlikely to be high-fiving. It was a gig. Job done. Like Ireland against Denmark, you might say that it was a goal-less draw.

The best thing to do, then, is look ahead to the next fixture. A big win there will banish any lingering ghosts. And with an album like Songs of Experience to push, the likelihood is that there will indeed be big victories ahead.