Just as people get the government they deserve, so Radio 1's breakfast show has a habit of reflecting much of what's happening outside the platinum disc-lined walls of Radio 1. Consider late-70s host Dave Lee Travis, whose open-shirted, hirsute exterior held a mirror ball up to the disco fever sweeping the nation, his no-nonsense straight talk offering a safe pair of hands with which the BBC could keep punk at arm's length. There have been some famous instances where the breakfast show host is woefully out of step. In 1984, for instance, Mike Read might have felt that he was speaking on behalf of the nation when he refused to play Frankie Goes To Hollywood's "Relax", but when it went on to sell almost two million copies, he proved embarrassingly out of step with Radio 1 listeners.
But, more frequently, it's possible to pick out key moments in recent history and see them echoed somehow in Radio 1's choice of breakfast show host. In the mid-1990s Chris Evans arrived at the station during the summer of Britpop in an explosion of booze and late nights.
Anybody hoping to recall the blind optimism of May 1997, meanwhile, need only look to the idealistic appointment, just three months earlier, of the most ill-suited breakfast team in Radio 1's history. Mark & Lard's fish-out-of-water schtick was a nice idea but listening figures slumped, justice was swift and their tenure lasted just eight months. Two months after Princess Diana's death, and with a new (if temporary) sense of responsibility hanging over the media, Radio 1 drafted in the talented but conspicuously serious Kevin Greening to co-present with Zoe Ball and her perky brand of post-ladette morning chit-chat.
Fast-forward to 2012, and the announcement that the station's often controversial breakfast host Chris Moyles will be leaving his show in September. It's worth noting that the Chris Moyles who first appeared on Radio 1 in 1998 is not the same Chris Moyles who departs in 2012. While his brash style may still not be quite to the tastes of your average Today listener, the tedious misogyny of old has evaporated along with a lot of the riotous "zoo format" whooping and hollering. Quite simply, he's grown up. To his critics, though, the bloated excess that characterised Moyles' early years, and the way in which he clung to his position despite the perceived best interests of the public, may have echoes of recent developments in the banking world. If that's the case, his perhaps reluctant resignation would make Moyles the Bob Diamond of cornflake commentary.
His replacement will be 27-year-old Nick Grimshaw, a regular face on London's party circuit. Fashionable clothes suit him and his career so far – presenting Channel 4's youth strand T4 and various lower-profile shows across Radio 1 – has showcased a cavalcade of haircuts.
While you could argue that the first Radio 1 breakfast show host, Tony Blackburn, was cool by default – Britain was swinging and so, in time, would be Blackburn's medallion – this newest recruit is the coolest of the lot. Unusually for someone so immersed in the more credibility obsessed end of pop, Grimshaw is also incredibly likeable: he has an affable and unselfconscious personality that makes him a naturally funny broadcaster.
In a way, landing in the middle of a Radio 1 purple patch makes Grimshaw's job even harder. If the station were on its knees he could enter majestically – as Moyles, the self-proclaimed "Saviour of Radio 1" did in the late 90s – and work his magic. As it is, he's picking up Moyles's huge audience of seven million, and will probably lose many of them. But that is, in a way, the point: Radio 1's average listener is 32, but the BBC station is supposed to be serving 15- to 29-year-olds.
Key to Grimshaw's success will be the way that he grasps mainstream culture just as instinctively as he grasps the music and fashion from the fringes. He's smart enough to know that he's been wheeled in to help make Radio 1 young again – not cool – and that it's a mistake to conflate the two. Looking through some of Radio 1's previous breakfast hosts, he'd be right. Steve Wright, who hosted the show from 1994, was hardly a trendsetter; Simon Mayo in the Eighties was not famed for pushing back the boundaries of style.
The breakfast show is no place for niche broadcasting, and Grimshaw's mix-and-match approach to popular culture means his appointment – like many a predecessor – reflects perfectly the era experienced by Radio 1's target audience. Grimshaw talks with ease to a generation more blissfully fractured than any before.
In fact, it's probably a generation on the verge of thinking it does not need radio at all, but it does because radio is brilliant, and Radio 1 has to show them why. With the traditional radio format struggling to stay relevant for many young teens, it's the job of Radio 1 and its flagship show at breakfast to turn young teenagers into lifetime radio listeners: that fight will be won or lost in the next decade.
If Nick Grimshaw stays in the breakfast slot for as long as his predecessor, by the time he leaves he will have either saved UK radio or killed it forever. No pressure, then.
Tony Blackburn: 1967-1973
Daily Disc Delivery, as it was then listed in the Radio Times , was the first show broadcast on the fledgling Radio 1 in 1967; but that didn't stop its first DJ clarifying any confusion by referring to it as The Tony Blackburn Show.
Chris Moyles: 2004-September 2012
"The saviour of early morning radio," according to himself, and "DLT-in-waiting", according to John Peel, Moyles bulldozered through the many critics who thought his approach boorish and arrogant, and new listeners kept tuning in, boosting ratings to 7.7 million.
Chris Evans: 1995 - 1997
Evans arrived giddy with the success of The Big Breakfast on Channel 4, spearheading Radio 1 controller Matthew Bannister's attempts to rejuvenate the station. The Ginger One took the zoo format, added booze, sex and outrage, and swiftly attracted 600,000 new listeners…
Chris Evans: 1995 - 1997
… but then came the boozy benders, the absences, the audience complaints. After 19 rollercoaster months, the station's most exciting DJ quit when his demand to take Fridays off was rejected.
Mark and Lard: 1997
After the Evans excesses, this was a stylistic volte-face from the Radio 1 controller – but the laconic, downbeat Mark Radcliffe and Marc "Lard" Riley were not what listeners wanted over their Coco Pops. They were moved, successfully, to the afternoon slot.
Sara Cox: 2000-2003
Cox inherited the Breakfast Show from Zoe Ball, and her breezy style quickly swelled viewing figures to 7.8 million. But she laboured under the "ladette" label, culminating in the decidedly off-colour comment that the Queen Mother "smelt of wee".