1. Richard Branson, Tycoon
An unexpected and, to some of our panel, controversial number one, the founder of Virgin Group (or "the smiley man with the beard", as he's styled on his blog) is a bigger force in social media than many people realise. Already an investor in Twitter, Branson has recently put funds into blogging platform Tumblr and into Twitter founder Jack Dorsey's new mobile payment scheme, Square. And in the past year he seems to have devoted increasing energy to making a name for himself in the Twittersphere.
His first tweets appeared in 2008, reassuring the public about his safety during his unsuccessful record attempt at sailing east across the Atlantic. These days he holds forth more frequently, on a range of issues, from Russian drug policy to office romance, cervical cancer campaigns and advertising for crew for Virgin Atlantic.
Hardcore Twitterati may be alienated by the corporate nature of some of his output, and by his reluctance to reply to his followers' comments.
But the warm, blokeish, man-of-the-people persona that has served him so well in the past has clearly struck a chord on Twitter, and no one can accuse him of ignoring the wider world. Recent themes include the decriminalisation of drugs, the democratic deficit in the Maldives – and a campaign for condom machines in ladies' lavatories. His 1.8 million followers retweet him avidly, and when Branson takes up a cause the effect is considerable. He is also recurrently enthusiastic about the doings of his family, and about his ambitions to travel in space.
Branson is bound to be gratified by his No 1 ranking. During a recent Twitter Q&A he was asked what the biggest regret of his career was; he replied: "Not starting Twitter."Follow @richardbranson
2=. Sarah Brown, Campaigner
The modest queen of tweeting has had to give up the crown she won in the inaugural Twitter 100 last year. But Sarah Brown's pre-eminence remains remarkable: her transformation from Prime Minister's wife to formidable campaigner is almost entirely attributable to her savvy use of Twitter. Her huge and loyal following allows her to make a real differences to causes such as PiggyBankKids – which helps vulnerable children – and the White Ribbon Alliance for Safe Motherhood. At the launch of her book Behind The Black Door last March, she threw a party for followers and spoke of her gratitude to the medium as a channel for promoting her causes. But her real secret is her Twitter persona: she's engaged, friendly and approachable, paying particular attention to people who are also named Sarah Brown.Follow @SarahBrownUK
2=. Alan Carr, Broadcaster
A genuine Twitter star. Promotion of his TV show, Chatty Man, has been siphoned off to a separate Twitter account operated by a girl called Sam who works "from a cell", according to Carr. This frees up the man himself to fill his timeline with air kisses to fellow celebs and greetings to fans who, for the most part, shower him with praise. (The sadly inevitable homophobic abuse is simply ignored.) The result is a Twitter output that is engaging, upbeat, funny and a occasionally a bit crazy. Carr once marshalled the Twitter community in an attempt to land the role of Laverne Hooks in the upcoming Police Academy film. It failed. Hey-ho.Follow @AlanCarr
4=. Ricky Gervais, Actor and comedian
You don't have to be a signed-up member of the Twitterati to have felt the fall-out from Gervais's activity in the medium. A spate of tweets last year using phrases such as "Good monging everyone", "Night night monglets" and "Two mongs don't make a right" provoked a furious response from disability campaigners and others who saw nothing funny about using a word that appeared to mock people with Down's syndrome. Gervais's defence was robust (if not entirely convincing): "Well done everyone who pointed out that Mong USED to be a derogatory term for DS [Down's Syndrome], Gay USED to mean happy. Words change. Get over it." Nearly two million followers (or "twonks", as he calls them) appear to have done so.Follow @rickygervais
4=. Rob Brydon, Actor and comedian
The showbusiness polymath (actor, comedian, impressionist, singer, television and radio presenter) has adapted to Twitter with predictable ease. With irons in so many creative fires, Brydon has plenty to say in terms of keeping his fans up to date. But it's when he has slightly less to say that his Twitter voice tends to be most distinctive – as in this:"Don't know if anyone's remarked but it's a bit cold in the UK today. This thong was a mistake, it's just not enough on its own"; or, more recently, this: "Wish I could think of something to Tweet about. Ideally something pithy, witty and not too long. Something that knows the value of economy."Follow @RobBrydon
4=. Chris Moyles, Broadcaster
His radio ratings may be under pressure, but his Twitter figures are in fine shape. The Radio 1 presenter recently passed the two million follower mark with a possibly tongue-in-cheek tweet referring to himself as the "pied piper of cool". Moyles's Twitter presence is pretty much a companion to his breakfast show; active during the week, sparse at weekends, references to the celeb lifestyle and occasional soliloquies to his beloved Leeds United. For someone who's been embroiled in the odd controversy over the years, Moyles keeps it relatively safe on Twitter; one minor spat with Lord Sugar, but that's par for the course.Follow @CHRISDJMOYLES
4=. Jamie Oliver, Chef
Britain's best-known foodie figurehead (and best-selling non-fiction author) is a prolific, no-nonsense purveyor of foodie tips and links and celebrity chit-chat. The size of his following is presumably explained by his likeability rather than his penetrating insights. Yet he is arguably at his most engaging when he tweets in anger: at rioters who smashed up his restaurant in Birmingham ("idiots"), for example, or, deliciously, at a follower who criticised his spelling ("Get lost you idiot im dislexic and i cant spell so stick that in your pipe! its better than being smug.")Follow @jamieoliver
8. Eddie Izzard, Actor, Comedian
Some Twitter users believe that comedians are obliged to be funny in 140 characters, and that bon mots and witticisms must be provided hourly in return for a follow. Eddie Izzard's high ranking debunks this fallacy. Izzard (assisted by "The Beekeepers", who occasionally chip in with news updates) keeps a tidy Twitter account that's as matter-of-fact as those of many of his followers: details of his running and triathlon escapades, advice on ice baths and courteous replies to those who offer encouragement. His online support of Ken Livingstone's bid for Mayor of London apparently foreshadows his own movement into politics ("in nine years' time," he recently predicted). In the meantime, he's a giant of the Twittersphere.Follow @eddieizzard
9. Derren Brown, Illusionist
Don't assume that, just because he follows only 29 people, Brown is a half-hearted Twitter enthusiast. In fact, there is an infectious enthusiasm about his regular updates, witty, interesting links and personal snippets about musical tastes (Bach) or public transport etiquette (don't bark into your mobile phone). The combined effect is a celeb Twitter account that's well above the average in that genre. And the master of illusion is generous, too: to celebrate his millionth follower in January he ran a Twitter-based competition whose winner would be whisked off for dinner with a friend at The Ivy.Follow @DerrenBrown
10. Jack Wilshere, Footballer
Fans of the provocative aperçus of Joey Barton or Rio Ferdinand may be disappointed to find that Arsenal's injury-sidelined young midfielder has been judged British football's top tweeter. Wilshere has had plenty of time for tweeting this season and has gathered a devoted following for his largely mundane discourse (mostly shout-outs to friends and family and updates on his condition) on sporting and other matters.Follow @JackWilshere
10=. James Corden, Actor
Recent Brits host Corden has mellowed since his first post-Gavin & Stacey burst of fame, but his reputation may be growing, not least through the stage success of One Man, Two Guv'nors. Yet he cuts a refreshingly modest, even humble, figure online, thanking friends and fans for their kind words. This doesn't make for a uniformly riveting account: it's mainly focused on Corden and his career. But every now and then a flash of attitude comes in – with retweets about Goldman Sachs and their tax and old people's winter fuel heating allowance – and there are also some heart-warming interactions – for example, thanking a fan for tweeting him the West Ham score while he was on stage for One Man, Two Guv'nors.Follow @JKCorden
10=. Stephen Fry, Actor, Comedian
Twitter without Stephen Fry would be unthinkable. For many, he is synonymous with the medium. A notable early adopter in 2008, he was a central figure in the medium's boom in popularity in the UK. An incident where he live-tweeted being stuck in a lift resonated far beyond the Twittersphere. Since then we've seen an online phenomenon christened the "Fry effect", where curiosities he unearths from the web and shares on Twitter cause servers to crash under weight of demand. Many authors and musicians are deeply grateful for his Twitter patronage; others, such as Daily Mail journalist Jan Moir, know the perils of provoking his ire. Fry himself is a sensitive soul, and not averse to a flounce when people get nasty, but he always comes back.Follow @stephenfry