Unusual volatility. Not words anyone wants to read when perusing the quarterly analysis in Volcano Week, you’d imagine.

But they are music to the ears of Music Week’s hard-pressed RAJAR analysts after a succession of quarters where we had to find new ways to say, “Not much happened, actually”.

No such problems with the Q4 2017 figures, with a number of stations posting growth figures that should draw admiring glances from even the much-less-strictly-audited world of streaming.

Streaming’s rock music ...