Social media is the way to stay ahead in the diplomacy game, says Roger Boyes.

When I became a foreign correspondent in the 1970s I found that an old university friend was working at the embassy. He was third secretary (culture). Every day the head of chancellery, before beginning “morning prayers” — the early in-house briefing — would tell my chum (good degree, wife) to check the toilets to see if everyone was in attendance. This accomplished, he would not be spoken to again for another 24 hours. Why do you put up with this? I asked him. “Some day I’ll get to do the same,” he said.

In his brilliant, often funny polemic, Tom Fletcher rails against the old and gone hierarchy of “public school prefects” and argues that another diplomatic archetype, “the gin-soaked amateur”, is “fading from history with a hiccup”. I know for a fact that this is overly optimistic.

He is right, however, to put the growing irrelevance of Foreign and Commonwealth Office hierarchies at the heart of Naked Diplomacy. The digital age, he argues, has made old-style diplomacy irrelevant. Diplomats have to understand the pace of technological change around them, adapt and adopt social media to help to project British power.

Fletcher knows whereof he speaks. As ambassador to Lebanon between 2011-15, he set up an opinionated, often cheeky blog called Naked Diplomat. Some posts, amplified by his tweets, drew a thousand online comments, television interviews, YouTube duels. Not everyone in the FCO was happy about this cultural revolution. Oliver Miles, a former ambassador to Libya, grumbled: “Stop the blogging ambassadors! . . . The issues with which ambassadors have to deal are better dealt with penseroso rather than allegro.” Fletcher picks up the reference to John Milton and says tartly: “Personally I think Milton would have tweeted.”

The issues underpinning Fletcher’s attempted revolution are not new; they centre on the relationship between strategic advantage, speed of communication and diplomacy. He cites the example of the master negotiator Shen Weiqin, adviser to an emperor of the Qin dynasty in 208BC.

The emperor’s armies had thrashed the rebellious Chu tribe, burying all prisoners alive (or “hard power”, as Fletcher calls it). Peace talks should have been easy, but the remaining Chu warriors had devised a new form of communication, setting up rested horses on key trading routes (“third century social media”).

As a result, in the midst of the talks they got word that the emperor was in trouble at home and drove a hard bargain. When Shen got home the emperor ordered that 999 body parts be cut from his star diplomat, the sequence of amputation to be chosen at random from a hat. Fletcher’s message: diplomats need to evolve to survive.

Having served three prime ministers as private secretary — Tony Blair, Gordon Brown and David Cameron — he has witnessed how leadership has changed during the 24-hour news cycle and the condensing of announcements down to 140 words for the rolling ticker of TV news, and the 140 characters permitted for a tweet.

John Kerr, Britain’s EU ambassador, famously concealed himself under the table at the leaders-only dinner on the Maastricht agreement in the early 1990s, handing notes to John Major. Today Cameron simply texts his ambassador outside the door.

Social media, says Fletcher, has changed the basic operating code of his profession. “For the first time we have the means to influence the countries we work in on a massive scale, not just through elites.” It is digital intervention. Fletcher has already passed recommendations to the FCO about how to put it into practice. One is that those diplomats who do hard language courses should emerge fluent enough to tweet in the host language and argue British policy on live television.

Text messages should replace the ponderous note verbale that ambassadors have to send to their host governments every time they want to leave the country for a few days. If you are angry with your host country, how much more effective to tweet your displeasure and mobilise public support. Secure emails should replace the antiquated system of diplomatic bags.

The book is not, however, a rant at the mandarins of King Charles Street, many of whom would be happy enough to upgrade the IT system if some cash could be clawed from the Treasury. It is for the most part just a cracking read. At one UN General Assembly Fletcher had to track the movements of Thabo Mbeki, the South African president, who was trying to avoid a tricky conversation with Britain about Zimbabwe. Fletcher staged an ambush to force the conversation.

Most fun was had, one suspects, in the company of Gordon Brown. “I once persuaded him to try a Japanese meal, but the culinary experiment was aborted after he ate an entire bowl of wasabi at one go.”

Fletcher is the master of the sting in the tale. “The best way to deal with neighbouring countries,” he writes, “is to appease, bribe, divide, punish, deceive, ignore or bluff, a set of approaches that have dominated Anglo-French relations for most of history.” Of the great and twisted French aristocrat, he writes: “Marquis de Sade observed (though his objectives were rarely diplomatic) ‘conversation, like certain portions of the anatomy, always runs more smoothly when lubricated.’ ” Too much information? No such thing, according to the Fletcher credo.

And he serves up plenty of tips from the corps diplomatique. Placement at the dinner table has long been a diplomatic tinderbox — in 1768 the Russian and French ambassadors to London duelled because of their relative position in the diplomatic box at a court ball. Alphabetic placing has eased the crisis, but Britain has rebranded itself as the United Kingdom so that it gets a seat close to the US — “and safely clear of the difficult group of countries whose names begin with ‘I’ ”.

Out of these anecdotes Fletcher draws metaphors for the changing world of diplomacy. A British banquet is logical, he says, following rules. Today’s world is more like a Lebanese meal: anarchic, chaotic, because power is shifting away from elites to networks. “I am working in a job where I represent governments, and governments are becoming weaker, compared to other sources of power, and within government diplomats are becoming weaker compared to other bits of government.”

Fletcher is passionate about the changes under way and gets a little carried away with the whiff of insurgency. “It is possible to imagine a conference, say on climate change,” he muses, “where a world leader will be tweeting from inside the meeting in a way that builds pressure on his counterparts from their own public, all amplified by the more trusted voices, the Malalas and the Bonos, outside the room . . . fluid, interactive and exciting diplomacy.”

I think we can live without that kind of excitement. A line has to be drawn between the old zipped-lips diplomacy, when envoys thought twice before saying nothing, and manipulative populism. As one adviser says in the book, it is difficult to identify a hashtag, supposedly a mobiliser of public opinion, that has changed anything. Remember #bringbackourgirls? Most of those Nigerian girls are still missing. Digital tools are sometimes useful, but not against self-isolating brainwashed terrorists.