IT HAS seldom been easy to be Archbishop of Canterbury. The unfortunate Alphege was murdered by drunken Vikings who pelted him with animal bones; Thomas Becket was famously struck down in his own cathedral; Simon Sudbury was, less famously, beheaded by a mob during the Peasants' Revolt; Thomas Cranmer was roasted alive in Oxford; and William Laud was beheaded on Tower Hill.

Statistically, it is one of the most dangerous jobs in Britain - far more risky than being a farmer, fisherman, deep-sea diver, or construction worker. Historically, more than half those appointed have died in office, and one archbishop in every 21 meets a violent end.

It is not a safe or comfortable office to hold. Today, archbishops do not find martyrdom listed on the job description, but they quickly learn to accept that character assassination comes with the territory.

No man (and, for now, the post is gender specific), on receiving the official letter, will view the invitation lightly. He will wonder not only if he has the gifts required to do a seemingly impossible task, but also whether he will be thick-skinned enough to cope with the welter of criticism that will inevitably come his way. Much of it will be phrased in highly personal language that is sometimes insulting, and often very hurtful to both him and his family.

AN ARCHBISHOP can perhaps brush aside the long letters scrawled in green ink that prophesy his eternal damnation. All public figures receive deranged missives. If they are shielded by an efficient team, they do not need to see them. Most such letters can be binned, although one politician used to send a reply that began: "I am sorry to inform you that someone who is clearly insane is using your name to send me insulting correspondence.

More hurtful, perhaps, are the criticisms that appear in print. Journalists have no qualms about publishing sweeping and colour-ful diatribes when they take issue with an archbishop's opinions.

Sometimes, debating points are spiced with personal observations. One commentator who disagreed with Dr Rowan Williams's views on the economy accused him of being "remarkably insensitive about other people's unemployment", and added: "Perhaps it's because he has never been unemployed himself, having mostly gone straight from one cushy number to another, now culminating in a very comfortable berth in Cambridge."

Most hurtful, perhaps, are the words of fellow Anglicans, especially if they were once allies and supporters. One cathedral provost, on hearing of Dr Williams's retirement, recalled in his blog how he had "rejoiced greatly" when Dr Williams was appointed. "How wrong I was," he wrote. "Personal loyalties were put aside. Personal convictions were shelved. Personal integrity was mangled in unseemly public displays of incompetence. Rowan Williams's obvious intellectual gifts were squandered." Ouch.

WHY does the Archbishop of Canterbury find himself on the receiving end of so much personal criticism? He holds a godly office, he may well have come to it reluctantly, and, whatever his mistakes, he must be credited with doing the best he can in an imperfect world.

One reason is that Anglicans fight their respective corners with passion, and the Archbishop of Canterbury inevitably becomes the lightning conductor at the centre of every Anglican thunderstorm.

Criticisms levelled at him are often couched in personal terms because, thanks to modern media exposure, the holder of the post is a familiar figure. He is centre stage at such national events as royal weddings. His face is instantly recognised by millions, and not just churchgoers.

While only a few people close to an archbishop know the man in depth, thousands think that they know him well enough to trade opinions in shorthand, caricature images. This tendency has increased of late with the advent of the social media. Twitter positively encourages the exchange of short, ill-considered opinions.

Dr Williams's popular image was established early on. "Scholarly", "deep", and "spiritual"; but, simultaneously, "unworldly", and lacking both "street cred" and "political nous".

OF POSSIBLE successors, some already have an image that they will find hard to shift. In Twitter terms, Dr Sentamu is seen as "populist" and "decisive", and yet also, by way of counter-balance, "gimmicky" and "authoritarian". Richard Chartres is noted for "gravitas", but thought of as "too much an establishment figure".

Should a lesser-known figure be appointed, he needs to remember that first appearances are important. The impression that he creates at his first press conference or photo shoot will, for good or ill, be hard to shift, once established.

When, as the years go by, he feels overwhelmed by the hurtful things that will inevitably be said about him, the next Archbishop should remind himself of his key, non-constitutional position. Besides being a diocesan bishop, a member of the House of Lords, and the public face of the Anglican Communion, he is also to many Anglicans - indeed, to many British people - a focus for their own irritations and hang-ups. When Anglicans are disappointed or confused, the Archbishop takes the blame.

Whatever negative media image he attracts - "unworldly", "light- weight", "all things to all men", "out of his depth" - he must constantly remind himself that such shorthand put-downs are always too glib to be fair. He must recognise that his destiny is to disappoint some, perhaps many. The new Archbishop needs to worry most when he is not attracting the brickbats and insults. That is the time to re-read Luke 6.26.

 "Woe unto you , when all men shall speak well of you!"

Ted Harrison is a former television producer, and a former BBC religious-affairs correspondent.