Slime & Reason, the fourth album from London wordsmith Rodney Smith, aka Roots Manuva, is a thrilling fusion of grimy rap, reggae tips and catchy hooks. It’s proof the four or so years since Awfully Deep have not been spent in vain. This is not a new sound for Manuva, but is a late fugue in a progression that started a decade ago now with Brand New Second Hand. And I don’t think it’s finished. This isn’t a glaring finale – in fact I don’t think Manuva has even peaked in projecting his musical vision – but the upwards trend continues. Slime & Reason is deep, sad, funny, whimsical, funky and, of course, a rapper’s delight.

Kicking off with the rollicking Again & Again, a pure synthesis between hip hop, ragga and reggae, Roots is given room to display his uncanny rapping talents. The trebly rhythm works as an easy counterpoint to his clear, deep voice. Next up C.R.U.F.F., with its pumping bassline and submarine blips, is a laid-back rap track on which Manuva puts forward the simple plea: Why can’t he say what he wants how he wants? Following is Do Nah Bodda Mi, an upbeat, dancehall track that shows breadth and diversity.

And then comes Let The Spirit – arguably the best track on the album. Minimalist beats grow and grow, layer upon layer, building the onion like an experimental music track. Then the main melody kicks in, almost like the backing track to Scarface, and somehow the whole thing becomes a classic rap song with a distinct and interesting sound.

The slower 2 Much 2 Soon is perhaps the first track on the album where it’s all about the lyrics. “If I could only make you understand, then I might make this place a perfect land, but there’s too much too soon, too little too late,” laments Roots. The more playful Do 4 Self comes next, with high pitched squawks, a bubbling bassline and heavy synth riff that rises and falls with the oft-repeated chorus. The Show Must Go On continues on the theme – like a different riff on the same sound, but slowed down. With Studio One overtones, it’s a reggae track with a slow hip hop beat. If you’ve ever heard Johnny Osbourne’s Truth and Rights, I think this’ll sound like a tip of the hat to a different era.

Slime & Reason grows on you. While on previous albums there’s been, perhaps, better tracks than anything on this album ( Colossal Insight for example), there’s a sharpening of musicality here. If you’re partial to reggae, hip hop, soul, grime or dancehall, you’ll be pleased by the way Roots Manuva has teased out the central aesthetics and made them his own.

Slime & Reason is out now on Big Dada through Inertia.