It's difficult to recollect a more maligned musical movement than the early-90s shoegaze scene. Initially championed by the music press, its prime movers were rapidly dismissed as dilettantes and showered in critical opprobrium largely for the heinous crime of being middle class and originating from the home counties.

Thames Valley five-piece Slowdive suffered such criticism more than most, but recently reformed and tonight begin a European tour 20 years to the week since they last played live. Yet what is remarkable is not how dated they sound but how extraordinarily well their sheer, sumptuous guitar arabesques have aged.

Their defining feature remains layers of fuzzy, barbed guitar, distorted by copious use of effects pedals into a spectral, amorphous haze. This exquisite aggregation lends a dense, profound quality to their music: gorgeous washes of sound, such as the early track Catch the Breeze, are both hearteningly intense and possessed of the kind of piquant, clear-eyed melodies that the Byrds would have coveted.

Once a bowl-haired waif, singer and guitarist Neil Halstead is now a stocky, hirsute figure, but alongside him co-vocalist Rachel Goswell remains a beatific presence, contributing whispered harmonies through a serene smile. The blissed-out Souvlaki Space Station drifts at a glacial pace to a Mogwai-like crescendo, its drone turning a packed, rapt audience into a sea of nodding dogs.

The group transform Syd Barrett's Golden Hair into a translucent shimmer, then encore with the mellifluous siren call of 1994 single Alison. There is no new material as yet, but on this assured display, Slowdive's unexpected return may prove one of this year's most welcome surprises.

• At Latitude festival on 18 July. Details: latitudefestival.com.