Like the universe itself, it starts with an explosion and expands to barely comprehensible proportions. With Radiohead, though, you can still hear the eruption that started them in earnest: scoot to ‘Pablo Honey’ – the unexceptional debut CD from Parlophone’s freshly-minted box set (or, if you were quick, limited edition USB stick) – and press play on “Creep”. One minute in, Jonny Greenwood’s famous powerchord surges into an amp that can barely take it, and nothing can quite be the same again.

Fifteen years later, it’s still impossible to understand what followed without reference to that one song. It was, after all, the pressure to emulate “Creep” that sent Radiohead hurtling into creative paralysis in the sessions for ‘The Bends’. Only by addressing the problem on My Iron Lung (‘Here is our new song/Just like the last one’), did Thom Yorke finally threw open the creative floodgates. The classic status of ‘The Bends’ has, however, never sat easily with Radiohead’s frontman, dreamy, drunken consolation songs like “[Nice Dream]” apparently leaving him feeling exposed.

Small wonder that since then, Yorke’s move towards deliberate obfuscation has intensified. He still writes great songs, albeit few with the unnerving emotional clarity of “Lucky” or “Let Down” from ‘OK Computer’. But had the acuity of Radiohead’s musical instincts wavered, they would have lost most of their fanbase at this point. The thing that strikes you about ‘Kid A’ and ‘Amnesiac’ now – in particular the childlike aspergers pop of “Everything In Its Right Place” and either version of “Morning Bell” – is just how melodic they are.

If there’s a poor relation in the Parlophone box, it’s probably the group’s final album for the label. Having set new standards of innovation, ‘Hail To The Thief’ saw Radiohead judged harshly against them by some. Yet the best songs on their 2003 opus – the oil-can disco of “Where I End And You Begin”, the windscreen-shattering terror of “Sit Down, Stand Up” – are among the finest by any band in recent years.

Four years on, unanimous praise greeted In Rainbows – in particular, the febrile “15 Step” and the baroque beauty of “Faust Arp”. Eight more songs complete the physical release of Radiohead’s seventh album. That “Mk I” kicks things off with the same piano note that concluded the download version suggests these songs are not so much an appendage to ‘In Rainbows’ as a continuation of it.

Certainly, they’re anything but leftovers. With strings that sound like Bernard Herrmann conducting the Love Unlimited Orchestra, the shuffling fever-funk of “Down Is The New Up” reaches a state of grace few bands ever get to achieve. But will any of these new songs come any closer to telling you where Radiohead fit into the prevailing music climate? Surely, what we love about Radiohead is the fact that they don’t. You can still imagine Thom Yorke casting an eye around at the competition and exclaiming, “What the hell am I doing here?” And so, the “Creep” effect continues.

PETER PAPHIDES