Pet Shop Boys, Tower Of London, London

Given the nature of the Pet Shop Boys' last London appearance, you could have been forgiven for wondering which way the gun turrets were pointing on the cruiser HMS Belfast, on the Thames's opposite bank. For, having last year provided a live soundtrack in Trafalgar Square to that homage to the Russian Revolution Battleship Potemkin, tonight Neil Tennant and Chris Lowe put on a show in one of the most abiding symbols of royal authority.

The Pet Shop Boys' latest album, Fundamental, has delivered a return to form after the stripped-down aesthetic of 2002's Release, even if the duo were nowhere near as authoritative with the material as they were on the hits that dominated the set. They have always been best at mixing dry wit with disco beats, so it was no surprise that "Left to My Own Devices" caused the first wave of onrushing fans to take the bouncers unawares. Then, the dramatic "Suburbia" got everybody up on their feet.

All the while, the theatrical designer Es Devlin's set went through its miraculous changes. At first, the stage was bare apart from a box out of which Lowe and Tennant appeared. Glowing with fluorescent tubes and back lights, this unfolded into a huge backdrop that displayed images - net curtains for "Suburbia" - and provided a platform for their dancers.

This pair of graceful movers and two backing singers both aped the duo's dress: Tennant's black top hat and Lowe's fluorescent yellow hoodie. With Tennant still an uncertain front man, the dancers had the run of the stage. Not that this was any excuse for Tennant's tentative behaviour: his voice was weak and he mumbled between songs, especially frustrating when the duo played new material. It didn't, however, spoil the effect of possibly the first protest song about ID cards. "Integral" was satire delivered with bristling intent and Lowe's most compelling beat since the mid-Nineties.

"The Sodom and Gomorrah Show" finally lived up to the potential suggested by its title, thanks to Lowe's driving beats, while the obvious Blair'n'Bush put-down "I'm with Stupid" came across strongly. But tonight was really all about nostalgia, for the Eighties commentary of "Opportunities" and the irrepressible, celebratory camp of "Go West". The most memorable image, though, came with the obscure album track "Dreaming of the Queen", a heartstopping lament sung to images of Diana, Princess of Wales's funeral cortège.