Britain's new top civil servant says he wants to kill off the Sir Humphrey stereotype

And, just to show he means it, Sir Bob is the first person in the post to take up social networking

As anyone familiar with the long-winded, convoluted language of television's Sir Humphrey Appleby knows, civil servants are seldom blessed with brevity or clarity.

But Whitehall's most senior mandarin has taken to Twitter to "kill off" the stereotype of the bowler-hatted bureaucrat epitomised by Yes Minister's most famous character.

The new head of the Civil Service, Sir Bob Kerslake, is the first person in this top post to take up social networking. And while his predecessors have remained in the Whitehall shadows, dealing only with civil servants and ministers, Sir Bob has been engaging directly with the public in 140 characters since he began tweeting as @sirbobkerslake last month.

The decision to join Twitter may raise eyebrows among defenders of traditional Whitehall, where discretion and anonymity are seen as part of the job. But speaking to The Independent on Sunday, Sir Bob, who by yesterday had a modest 1,579 followers, said he joined Twitter to break down the barrier between the Civil Service and the public.

"If I can do anything to kill off the stereotype of the Whitehall mandarin I would be a very happy man," he said.

"The reality is the Civil Service is predominantly not in London, predominantly on average salaries, and predominantly dealing with public services. It's a pretty small number doing the policy work at the centre, very different from the stereotypes."

Sir Bob, 56, added: "Part of the reason for doing it is to more effectively communicate with our 440,000 civil servants.

"But also, if we, as senior public servants, want to communicate with people who often see us as faceless bureaucrats, part of that is using the media that they themselves use and feel comfortable with."

Sir Bob became head of the Civil Service in January when Sir Gus O'Donnell retired from this post and as Cabinet Secretary. The job was split in two, with Sir Jeremy Heywood becoming Cabinet Secretary. Sir Bob added that the Cabinet Office was keen for the new leadership to "demonstrate some different approaches to communication" – although Sir Jeremy has yet to join Twitter.

Responding to tweets on everything from the honours system to the London Marathon, Sir Bob has been tweeting about his recent visits to Sheffield and Suffolk. He said he hoped his Twitter use would encourage more civil servants to tweet, although admitted there was a fine line between honesty and indiscretion. "It is a personal medium. Organisations do use it in a corporate way, but the most effective people using Twitter, use it personally. That is to some extent, more risky. It is very immediate, very direct.

"You have to be careful what you say and how you say it. But there are still meaningful things you can say."

Sir Bob, who is also permanent secretary at Eric Pickles's Department for Communities and Local Government, joined the Civil Service in 2010 after a career in local government, including being chief executive of Sheffield City Council from 1997.

He is working with the Cabinet Office minister Francis Maude on other ways to open up civil and public services. These include making the Civil Service more flexible for families by allowing staff to do more work from home, which will start during the Olympics but continue as a regular practice.