Even its author admits that a 20-page strategy paper for government departments on how to use Twitter might be regarded as "a bit of over the top" for a microblogging tool with a limit of 140 characters a message.

Indeed, the 5,382-word official "template",which translates into 36,215 characters and spaces, would need roughly 259 separate tweets to put the word around Whitehall using Twitter.

But its author, Neil Williams, who describes himself as head of corporate digital channels at Lord Mandelson's Department for Business, Innovation and Skills, admits that when he sat down to write a proper plan for his department's corporate Twitter account, "I was surprised by just how much there was to say ‑ and quite how worth saying it is."

Whitehall's official use of Twitter was pioneered by Downing Street, the Foreign Office and the Communities and Local Government department.

Their low-profile experiments have grown into a regular feature of their official digital output.

Now Williams, a self-confessed web geek, has turned his template into an official Whitehall Twitter guide and posted it on the Cabinet Office's digital engagement blog.

He suggests that nothing too onerous is involved. Each department's "digital media team" should only need to spend less than an hour a day running their Twitter streams. A quick discussion of potential tweets at the morning press cuttings meetings should be followed by emails to minister's private offices to gather more material, and any incoming messages should be replied to.

However, the idea of official government use of a tool that provides a confidential and confessional glimpse into somebody's personal life and views appears at first sight to be something of an oxymoron.

The official guide seems to acknowledge this when it recommends that exclusive content such as "insights from ministers" and "updates on their movements" in a light or humanised style will be needed for the Twitter stream beyond the "business as usual" content of daily press releases and announcements.

It also concedes there is a problem with one of the basic Twitter features, the ability to "follow" any other users. It admits that if government departments start following individual users on Twitter uninvited, this may well be interpreted as "interfering 'Big Brother'-like behaviour".

However, once anyone does follow a Whitehall Twitter stream it recommends they should automatically be "followed back" on the grounds that it is not only good etiquette, but could result in a poor Twitter reputation if not done ‑ and in extreme cases could lead to the account being suspended.

In urging his fellow Whitehall civil servants to use Twitter, Williams sets out several grounds rules for the kind of content that needs to make it work:

• Human: He warns that Twitter users can be hostile to the "over-use of automation" - such as RSS feeds – and to the regurgitation of press release headlines: "While corporate in message, the tone of our Twitter channel must therefore be informal spoken English, human-edited and for the most part written/paraphrased for the channel."

• Frequent: a minimum of two and maximum of 10 tweets per working day, with a minimum gap of 30 minutes between tweets to avoid flooding followers' Twitter streams. (Not counting @replies or live coverage of a crisis/event.) Downing Street spends 20 minutes on its Twitter stream with two-three tweets a day plus a few replies, five-six tweets a day in total.

• Timely: in keeping with the "zeitgeist" feel of Twitter, official tweets should be about issues of relevance today or events coming soon.

• Credible: while tweets may occasionally be "fun", their relationship to departmental objectives must be defensible.

Alongside the promised tweetable content of minsters' thoughts and reflections following key meetings and events is something rather more sinister sounding called "thought leadership". Also known as "linked blogging", the idea is that by highlighting relevant research, events, awards and other action elsewhere on the web, the department's Twitter feed gets a reputation as a reliable filter of high quality content.

It even holds out the promise of "crisis content" in which the Twitter feed becomes a primary channel alongside the official website for up to the minute guidance and advice in the event of a major incident.

Perhaps the biggest stumbling block is that in true Whitehall tradition everything that goes out has to be approved and cleared first. So news releases are to be cleared for use only if they have first been paraphrased for Twitter. All other tweets have to be cleared by staff at information officer grade in the digital media team and colleagues in ministers' private offices and communications units have to be consulted as well.

The guidelines recommend that "light-touch controls" will also be needed to prevent "inappropriate content" being published in error such as embargoed news releases, information about the location of ministers that could put their security at risk, or other commercially or politically sensitive content. Steps are also to be taken to avoid hacking or vandalism of content.

But it is perhaps the "tone of voice" that is most troubling about the idea of Whitehall twitter stream. "Though the account will be anonymous (ie, no named officials will be running it) it is helpful to define a hypothetical 'voice' so that tweets from multiple sources are presented in a consistent tone (including consistent use of pronouns)," recommends the official template.

"The department's Twitter voice will be that of the digital media team, positioning the channel as an extension of the main department website ‑ effectively an 'outpost' where new digital content is signposted throughout the day. This will be implicit, unless directly asked about by our followers," it advises.

Williams, the author of this template, launched the first ever blog by a British cabinet minister. He admits he once ran a comedy website called idiotica.co.uk but the Cabinet Office confirm that his Twitter guidelines are genuine.