The album, the pair's only one for jazz imprint Strata-East records, marked a stylistic watershed. Typified by The Bottle, it had a more commercial, soulful sound that contrasted with the often unyielding tone of their earlier songs and Scott-Heron's spoken-word raps.

Where earlier albums, such as Pieces of a Man, are punctuated by minimal jazz backing rhythms, Winter in America is more orchestrated, lush and smooth, finding influence in the emerging funk and disco stirrings of black American music of the early 1970s.

With the possible exception of the hit single, the album's tracks also mark a shift in Scott-Heron's lyricism, away from didactic tours de force to a less abrasive, more considered, poetic style.

The punchy, visceral verses of his early work, which have latterly won him the sobriquet 'the godfather of rap', give way to stirring nostalgia for an idealistic past that never was and keening despair at social problems within black neighbourhoods.

However, that's not to say the album pulls any punches. As its title suggests, Winter in America lays out the singer's vision of a nation past its best and in a state of irreparable decline. Take The Bottle: despite its infectious groove, the grim portrait of alcoholism and abuse within America's black community is a biting critique of a society that places little value on its most down-at-heel citizens.

On the title track, the first poetic stanzas and lilting undulations evoke images of a beautiful country and people. But not far beneath the surface is a simmering anger at the ravages modernity has wrought on this utopia.

'From the Indians who welcomed the pilgrims/ And to the buffalo who once ruled the plains/ Like the vultures circling beneath the dark clouds/ Looking for the rain/ Looking for the rain,' he sings, later adding the sucker punch, 'Like the forest buried beneath the highway/ Never had a chance to grow/ Never had a chance to grow'.

Appealing directly to the cold war paranoia prevalent in the 1970s, Scott-Heron portrays the historical ravages brought upon the native American people, the American landscape and its resources as akin to a nuclear winter, the lifeless aftermath of an atomic attack. He sees a country battered, tired and demoralised by centuries of pillage in which 'ain't nobody fighting/ Cause nobody knows what to save'.

Winter in America sold slowly until the release of the catchy The Bottle, as his politically motivated audience took its time in realising the album's depths.

This landmark release by Scott-Heron - who died last May, aged 62 - has since been recognised as a cornerstone influence on the modern-day soul and funk played by the likes of Erykah Badu.