A large question-mark hangs over tonight's audience. It's about 5ft high and is being waved by a fan, alongside inflatable aliens and hammers. It refers to the quizzical nature of Delirious?'s name, but also punctuates this final gig of the band's tour: what next for Britain's premier Christian rock act?

Martin Smith, Delirious?'s lead singer, appears to know the answer. "We're doing it, aren't we?" he tells the clean-cut crowd, describing the group's forthcoming appearance at Glastonbury and the interview they have just given to a music monthly. He repeats himself later, rather more chippily this time, after thanking everyone for their help in getting their single to number 16: "Radio don't seem to be jumping on it but we're doing it, aren't we?"

What Delirious? are clearly doing is courting mainstream approval. They have recently released their second album, Mezzamorphis, a collection of songs that demand the description "radio-friendly". They are tuneful and slickly-produced exercises, scratching at the surface of Radiohead and gazing covetously towards Achtung Baby-era U2. It's the sort of bombastic music well-suited to religious concerns, although it also marks Delirious?'s attempts to expand their following beyond their mainly Christian constituency.

Matters of faith are still the subject matter of their lyrics, although somewhat more mutedly than before. One early example, I'm Not Ashamed (Of The Gospel), gets an airing tonight, as do other crowd-pleasers.

The evening's tone, however, is set by a new song, Bliss. Here, Smith places one foot squarely on the monitor and belts out lines such as "Rock'n'roll is everything" over a pounding beat and crunchy guitars. No cliché is left untouched as he holds his arms out wide, guitarist Stuart Garrard skips to the side of the stage, and images play on the screen behind.

Delirious?'s brand of rock'n'roll does reach a few melodic heights (Gravity, for instance) but generally gets grounded by its derivative nature. There are even echoes of Spinal Tap, with Smith appearing in jester's mask and smart suit for King Of Fools. Although the fans greet most songs fervently, there is little here to transport other listeners. "We're not where we want to be - that's true for us all, yeah?" says Smith towards the end. It's one of the few overt mentions of spiritual affairs, but applies equally to the band's rather more worldly ambitions. As it is, they're preaching only to the converted.