Elbow, Brixton Academy, London

"It's taken a while to get the recognition we've been getting. We've been a band 18 years. Before [guitarist] Mark and [keyboardist] Craig's sons can walk, hopefully they'll see their dads playing an arena some day," frontman Guy Garvey says to the crowd of 5,000 fans.

And it's true; in their 18 years the Manchester indie band have clocked up four critically acclaimed albums, and their latest, The Seldom Seen Kid, is their highest charting LP to date. This is the second time they have sold out Brixton, but by rights Elbow should be playing arenas. Garvey's words sum up the frustration of the band who have had to watch their peers – inferior both musically and lyrically – ride the crest of a wave.

Perhaps it's Elbow's refusal to play by the book and court the mainstream; they start tonight with the far from conventional opener "Starling", a rousing song that begins with startling trumpet fanfare, keeping listeners in its thrall.

Elbow are known for producing consistent albums rather than one-off singles. The closest they get tonight to a hit is the title song of their previous album Leaders of the Free World, with its mantra "But I think we dropped the baton like the Sixties didn't happen", and the newer "One Day Like This", which gets the crowd singing. Their March single "Grounds for Divorce" is even more effective live.

Tonight, Elbow's characteristic epic melancholy is made richer by the addition of a string trio. But Garvey keeps the mood light with his usual witty chat between each emotion-loaded song. It's this quick wit that has attracted so many of the band's new fans through his Sunday evening radio show on BBC 6 Music. "See if you can guess what [song] it is by the way we light the stage," he jests, as the tiny spots of light start swirling round the Academy as the band begin "Mirrorball".

Following a dynamic performance of "Forget Myself", Richard Hawley's surprise appearance to perform their humorous co-written duet "The Fix" is a welcome change of mood, and draws cheers of appreciation for the Sheffield star.

Whether or not Elbow get the commercial success they deserve, they remain consistent songwriters and an inspiration to many. And that, surely, is success.