Not too long ago, defiantly amateurish British bands were all the rage. With untuned guitars backing untutored singers, these groups wore their rough edges with pride, as if such a resolute lack of polish would somehow cleanse their music of the feckless sterility that characterized big-time rock.

These days, an opposite taste dominates. Although there are still those bands in Britain that prefer to roar in ill-mannered rage, more prevalent by far are acts that have slyly co-opted mainstream standards. It isn't as if they've sold out to commercialism, for most remain as alienated from the Top 40 as their forebears. Rather, it's that they've learned to apply the slick trappings of establishment pop. In many ways, these bands are as amateurish as ever, only now it can be advantageous.

If that seems a bit paradoxical, consider the Blue Nile, a trio of Glaswegians, whose first album, "A Walk Across the Rooftops" (A&M SP-65087), is one of the most striking debuts of the season. Paul Buchanan is hardly the most impressive singer to have come out of Scotland in recent years, although his voice manages to land steadily on pitch most of the time. Mostly his is an unassuming croon that at times seems to stretch to hit the high notes cleanly and will likely never lose its guttural edge.

For all that, though, Buchanan's singing is tremendously affecting. Part of it is that his lack of technique makes it hard for him to mask his emotions. Mostly, though, it's the way his simple performances fit in with the overall structure of the music.

The title track, for instance, deploys unexpectedly lush orchestration behind Buchanan's voice, lending his unstudied delivery a vulnerability that perfectly echoes the dazed romanticism of the lyrics.

Buchanan and bandmates Paul Moore and Robert Bell aren't exactly the most versatile composers around, and it could be argued that they rely far too heavily on trancelike repetition to make their point. But though their ideas may be steadily recirculated, there's never a sense of stagnation to these songs. Whether it's through the carefully layered loops that support "From Rags to Riches" or the steady churn that propels "Heatwave," the Blue Nile never pushes a good idea too far.

Shreikback has no use for carefully constructed dynamics. This quartet's music is all muscle and rhythmic energy, suggesting in its aggressively naive appropriation of funk an extension of the Gang of Four's approach to pop didacticism. Given that bassist David Allen is an alumnus of the Gang of Four, that can hardly be accidental, but where the Go4's last efforts were an uneasy compromise between dance-floor dynamics and agitprop polemics, "Oil and Gold" (Island 90276-1) makes no bones about either its politics or its musical preferences.

Taking a hard line politically is considerably more convenient for Shreikback, because this band's political position is far less clearly defined. Unlike the Gang of Four's plain-spoken commentary, which was Marxist in no uncertain terms, Shreikback's symbolism is such that a clear reading is almost impossible. Muddying the waters still further is the album lyric sheet, which renders their words in numbingly incomprehensible phonetic script.

All that would be forgivable were the band's musical perspective more coherent, but here too, Shreikback stumbles more often than it stands. "Malaria" kicks off the album with an agreeable jolt of adrenaline, as the rough-hewn vocals contrast against the slick, high-energy rhythm track. Unfortunately, it's mostly downhill from there. "This Big Hush" and "Nemesis" make much of the female backing vocals in terms of added volume, but otherwise seem locked into cliche'. Far better is the careful shading that supports "Faded Flowers" and "The Only Thing That Shines," two ballads that nearly overcome their lack of strong melodic content.

Similarly, the atmospherics that color most of the quiet numbers do little to bring the tunes into focus, while the rhythmic blare behind the uptempo numbers often ends up as mere mindless exertion.

In the end, the approach Shreikback takes on "Oil and Gold" is far too promising to be so haphazardly rendered. Given the progress this band has made, there is reason to hope for improvement; but if "Oil and Gold" is the height of Shreikback's musical ambitions, the band is headed for trouble.