Todd Rundgren, Royal Festival Hall, London

Since his mid-Seventies heyday, Todd Rundgren has always been preaching to the converted, so his religious-themed show is at least appropriate, though unlikely to extend his popularity beyond its current limits.

Since his mid-Seventies heyday, Todd Rundgren has always been preaching to the converted, so his religious-themed show is at least appropriate, though unlikely to extend his popularity beyond its current limits.

The stage set is ingenious, a series of five Gothic arch lighting rigs, one each for the four band members and a larger one for Rundgren. Fold-down keyboards attached to the rigs allow the bassist and guitarist to switch quickly between strings and keys, and the combination of lights and back-projections behind each of the four players' individual risers affords a wide range of illumination. The effect is akin to religious statues set in their own little niches, a notion accentuated by costumes that present them as a priest, a pope, a swami and an oriental monk. It's an amusing conceit, particularly since the drummer, notwithstanding his bishop's mitre and sunglasses, brings to mind Father Ted's fearsome Father Jack. Rundgren appears in three-inch platform boots, knee-length trousers, wraparound shades and a fetching ankle-length brocade coat, which is discarded during the first song.

The performance is in two halves, separated by the most leaden version imaginable of "Green Onions" - whoever thought this an appropriate vehicle for this quartet of unreconstructed prog-rockers needs their head examining: compared with the taut brevity of Booker T & the MGs' original, their solo-ridden version is an abomination. The first half features Rundgren in his pomp-rock mode, with a clutch of songs - four taken from his current Liars album - questioning religious precepts and assumptions. But while the impact of the opening "Truth" is tremendous, the rest of the set can't quite live up to it.

Although sensible and well-argued in many respects - "Fascist Christ" is especially pertinent in urging the separation of church and state - their effect is, if anything, diminished by the bombastic presentation. It's good advice delivered at a gazillion decibels, and more than once I found myself wishing Rundgren were doing solo acoustic renditions, as the melodies disappeared under the layers of keyboards and pummelling drums. This is the masculine half of the show - Rundgren's overwhelmingly male fanbase can be gauged by the enthusiasm with which the Net nerds in the audience sing along to "I Hate My Frickin' ISP" - followed, after a seamless costume-change, to suits of purest white (for the band) and garish orange (Rundgren), by the more feminine side.

For this latter half, Rundgren goes back to the church to recast himself as a soul crooner, opening with the light funk-fusion of "Soul Brother" before slipping into a series of extended pop-soul ballads, the best of which is the smooth, loping "Sweet". Nearly all are extended way beyond their acceptable length, the set eventually collapsing in on itself during seemingly eternal versions of "Born to Synthesize" and "Feel It". It's as if they can't find a way to finish these songs, the band just vamping over and over and over as yet another solo is tacked on to the end in a show of preposterous prog-rock posturing.

For non-believers - and even a few formerly diehard fans, as well - this was a gruelling service to endure.