Scott Mills may look the picture of the laid-back Radio 1 presenter, but he sounds, if not militant, then at least a little het up.
The issue which has riled him is gay rights, a topic the 36-year-old has been reluctant to speak about in the past for fear of being pigeon-holed as a "gay DJ". In something of an about-face, he is now planning a programme about homosexuality in Uganda, one of the most dangerous places to be gay on the planet.
"I'd quite like to do something serious. I'm sure it'll move me, and it'll also get the people off my back that say I don't do anything," he says. It is difficult to work out what he is more upset about: the parlous lack of gay rights in many countries or the people pestering him to do something about it.
One gets the sense that he has been corralled into using his high profile– more than six million listen to his early evening show – to advance gay causes. While Mills, who came out without fanfare in a newspaper interview in 2005, insists he is not the campaigning type, he has been working with charities such as the Terrence Higgins Trust.
"Some people just lend themselves to waving the flag, but I've never been like that," he says. "I get a lot of emails from people asking why don't I do more? Some gay people want me to go on air and say 'what about gay issues?', but I'm doing a mainstream daytime radio show, it is not a social affairs programme."
While a natural entertainer, the presenter is clearly wary of controversy, trotting out the party line on everything from the multi-million pound salaries of some BBC presenters – necessary to prevent them from being poached by rival stations, apparently – to the "great value" licence fee, and BBC Radio 6 Music's reprieve, which he describes as "the best PR they've ever had".
After six years presenting his own show, Mills is clearly comfortable in his own skin. So comfortable that he makes no bones about his desire to bag the coveted breakfast slot currently held by loudmouth DJ Chris Moyles. "It would be a brilliant challenge. If they offered me the morning show I'd be a fool to say no. My lifestyle lends itself to it now. I feel more centred, like I've got everything in order," he says.
The Hampshire-born DJ joined Radio 1 in 1998 as a presenter on The Early Breakfast Show after several years in commercial radio. In May, Mills's stellar rise was confirmed when he pipped Moyles to the post to win the Sony Music Radio Personality of the Year award – an achievement he describes as "unbelievable". He says that he cried after receiving the award.
"If you'd asked me a couple of years ago if I could have done it [the breakfast show] I'd have said no. I was going out too much, drinking too much."
While Mills may still be dressed like an overgrown teenager, in combat shorts and a bright purple hoodie, his huge Nike trainers dangling over the arm of the chair while he fiddles with his iPhone, he has undoubtedly grown up. This transformation is partly due to the stabilising effect of his partner of a year, with whom he has just bought a house in north London; "the slightly ghetto end of Crouch End", he insists.
Mills's fresh-faced appearance is testament to this healthy new lifestyle – he has given up the booze and hired a personal trainer – although he pleads exhaustion due to juggling his duty filling in for Chris Moyles while he is on holiday with rehearsals for the one-man show he will perform at the Edinburgh Fringe later this month.
Entitled The Bjorn Identity, the piece combines the plot of the Bourne Identity action film with the songs of Abba. "It is like in Mamma Mia! when they shoehorn the songs in," he says. "It'll just be me, with masks and other pre-recorded voices."
This follows on from the success of the DJ's first foray into theatre. That was in Edinburgh last year, Scott Mills: The Musical, which started out as an on-air joke but turned into a slick ensemble number which garnered positive reviews and was watched by one million people online. His Radio 1 shows will also be broadcast live from the city between 16 and 19 August.
"I can hold a note, but I'd never be a good stage performer. The idea terrifies me. I got into radio because it was a way of reaching lots of people without actually having to meet them," he says.
While Mills may plead shyness and insecurity, one gets the impression this is more out of habit than genuine feeling, and that it would take more than soloing Swedish pop songs to ruffle this presenter's feathers.