Richard Thompson doesn't have much in common with the prototypical happy-go-lucky rock 'n' roller. He plays an electric guitar, to be sure, but he doesn't think that life is a lark, and he doesn't know what it means to write a cute, clever little throwaway pop song. When he sings, there's pain and bitter resignation in his voice and his lyrics, and when he fires off a guitar salvo, there's intense feeling in that, too.

Perhaps that is why Thompson has for so long remained one of rock's great undiscovered talents-and why it has taken three years for his "I Want To See the Bright Lights Tonight" album to reach the United States. Through rock 'n' roll fans, like most people, want to be reassured, not challenged, Thompson, a refugee from the British folk-rock group Fairport Convention, is constitutionally incapable of spoon-feeding his listeners cheery sentiment.

Yet it is precisely this bleak, unvarnished honesty that makes "Richard Thompson:Live (More or Less)," a double-record set that includes the 10 songs released in England in 1974 as "Bright Lights," one of the best albums of 1977. There's not a single false note here:Thompson's lyrics shine with a steely, uncompromising integrity, a quality that his music, as tastful and controlled as ever, briliantly accentuates. Thompson's roots are in the folk music of the British Isles, and many of the songs on the album reflect that - "Poor Will and the Jolly Hangman," a leftover from his days with Fairport Convention, perhaps most of all. He often uses modern and traditional instruments together, as on "When I Get to the Border," where an electric guitar trades licks with a dulcimer, an English concertina and a krummhorn.

Odd as this combination may seem, it is most appropriate to Thompson's lyrics, which frequently have an oddly archaic flavor. His diction on "Down Where the Drunkards Roll" is right out of the 17th century, and his gallows humor also seems to have been derived from that period: "A man is like a rusty wheel on a rusty cart," he announces at the beginning of "We'll Sing Hallelujah." "He sings his song as he rattles along, and then he falls apart."

Though several of the most compelling songs are written in traditional ballad form, Thompson fleshes out most of his music with a rock 'n' roll rhythm section. The studio version of "Calvary Cross," which also appears here in a live, 13-minute rendition, begins with a swirling guitar solo that is reminiscent of the Beatles' "Love You To," and "Bright Lights" boasts an oompah, Salvation Army-style brass section.

The single most powerful song on the album, however, is also its simplest and starkest. "The End of the Rainbow " was ostensibly written as a lullaby for Thompson's infant son-and with its lilting vibraphone and delicate acoustic and electric guitar accompaniment, it actually sounds like a lullaby. But when the drums come in and Thompson begins to sing, the mood of the song suddenly changes.

"Life seems so rosy in the cradle,"Thompson sings to the child as the drums slog along, hinting at impending doom, "but I'll be your friend, I'll tell you what's in store. There's nothing at the end of the rainbow, there's nothing to grow up for anymore." Rarely has a pop figure enunciated such a sour view of the world, and rarely has he done so in so unorthodox and decptively soothing a fashion.

But that is how Thompson works, slipping the unexpected element into the most familiar of forms. He does if again on "The Great Valerlo," an allacoustic ballad which his wife, singer Linda Peters Thompson, performs. Her voice is tender and sweet, which only intensifies the impact of Thompson's sad tale of a tightrope walker. "We falter at the side, we stumble in the mire," she sings above the guitar, "fools who think they see the heights, prepared to balance on the wire."

This is strong stuff by pop standards, and obviously not suited to everyone's taste. But to alleviate Thompson's unrelenting pessimism, the overwhelmed, emotionally-drained listener can always turn to side three of the album, which contains a Fairport Convention interpretation of The Byrds' "Ballad of Easy Rider" and two lovely instrumentals, the traditional "Flee As A Bird" and "The Pitfall/The Excursion."