IoS pop review: The xx, Guildhall, Portsmouth Squeeze, Forum, London

The British trio are self-effacing to a fault. Meanwhile, Squeeze can still make a grown man cry

What a strange scenario this is: 2,000 people packed into a civic hall to see a band who aren't actually there.

The xx are absence made flesh. It's a paradoxical trick, but Romy Madley Croft, Jamie Smith and Oliver Sim have become one of the most successful British breakout bands of the decade – toppers of charts, winners of awards, covered by Shakira and Gorillaz, sampled by Rihanna, loved by seemingly every-one – by removing themselves almost entirely from the picture.

Self-effacing, even self-erasing, The xx are that rare, almost oxymoronic beast: a rock band devoid of ego. And that void echoes in their music. Not just in the gaping spaces left inside their sparse, less-is-more arrangements, but in the lyrics too.

In this sense, The xx are the most British of bands, their songs a musical equivalent of a drawing-room drama where muted, minor-key regret reigns and the important stuff is forever unspoken. And the chief players are Romy and Jamie, an uptight, repressed Limey version of Nancy & Lee.

Second album Coexist is marginally superior to the adored xx but will live in its shadow. It's pregnant with the fear of loss. On opener "Angels", which also opens tonight's set, Romy repeats the phrase "They would be as in love with you as I am", the conditional tense hanging in the air. On "Reunion", she muses "If I wait too long, I lose you from my sight, maybe tonight". You find yourself wanting to grab them by the lapels and compel them to sort it out (but where would that leave their muse?). Sometimes, like broken clocks, their thoughts coincide: "Why would you just leave me alone," they ask on "Tides" in uneasy unison, "when we have been close?"

All of which makes them a difficult sell as a live draw. The xx are not a band whose presence on a festival bill would have you crawling over broken glass to get a ticket. Pyrotechnics are not their style, and they don't exactly ooze on-stage charisma, lurking in a diffident blue gloom. Occasionally, Jamie – waistcoated and Brylcreemed – will loom forward, wrapping his microphone cable around his neck, or sing directly into Romy's guitar strings. But it doesn't matter how close he gets: the chasm between them remains. It's that big nothingness we've come to see.

BBC4's wonderful Squeeze night revealed the south-east London legends as having briefly been the least-likely occupants of an Eighties Cocaine Hell this side of Frank Bough. But if it felt weird hearing about them indulging in such rock'n'roll behaviour, that's only because in the three decades since their commercial prime Chris Difford and Glenn Tilbrook have been sanctified by pop history. For all the humanity of their biggest hits, there was a wonderfully unpleasant edge to Squeeze, particularly in the early days of John Cale-produced albums, lurid coloured vinyl singles, and loose affiliations with punk.

Take the offhand callousness of "Cool For Cats" on which Difford, (perhaps in character, perhaps not) delivers the single-entendre "I'm invited in for coffee/And I give the dog a bone". Or the pure filth of holiday memoir "Pulling Mussels from the Shell". Or the audacity of opening a song with the lines: "She was frigid as a Bible when she met her boyfriend Michael." Squeeze were never saints. But, on their half-dozenth comeback, they're welcomed as heroes. Opener "Bang Bang" is given a UK Garage makeover and finale "Goodbye Girl" is turned into a ukulele number, but in between, from a white hot "Annie Get Your Gun" onwards, Difford & Tilbrook don't mess with the formula. And what a formula: a lyricist who chronicles the minutiae of adult British break-ups with a poet's eye (wedding rings left by the soap, suitcases pulled from under the bed) and a singer with one of THE great rock'n'roll voices, a Deptford Lennon weaned on love not bile.

Tasters from forthcoming album Pop Up Shop are received politely, as are solo efforts, but it's the classics everyone wants to hear. The killer is "Up the Junction", one of the few songs that can make me cry. It's the sheer optimism with which the soon-to-be-abandoned narrator makes each sacrifice for his lover and their offspring that breaks the heart. Even the mundanity of the couplet "I got a job with Stanley/He said I'd come in handy" can reduce me to jelly, in a weak moment. You can keep all your Nashville weepies. Squeeze will do for me, all day long.

Paul Weller, Emeli Sandé and Miles Kane play a benefit for the homeless charity Crisis, hosted by Ben Elton, at the Hammersmith Apollo, London (Wed). Meanwhile, Motown legend Martha Reeves and the Vandellas play Oran Mor, Glasgow (tonight); Concorde 2, Brighton (Tue); Jazz Café, London (Wed, Thu); Eric's Club, Liverpool (Fri); and The Robin 2, Wolverhampton (Sun 23).