The Pope will arrive in Britain on 16 September in two capacities. He will emerge at Edinburgh resplendent in his regalia of head of state ("a red satin mozzetta trimmed with fur") to meet the Queen, who must, according to Vatican etiquette, dress in black - only Catholic queens can wear white in the pontifical presence. He must then change into more modest robes to conduct an open-air Mass in Glasgow as head of the Roman Catholic Church. In that capacity, he deserves the warmest of welcomes and the utmost respect. But as head of a state - sovereign of the Vatican City State and the Holy See - it is time to point out that this emperor really has no clothes.
The Catholic Church is the only religion that is permitted - under international law as interpreted by the Foreign Office, and at the United Nations - to claim the privileges of sovereignty and statehood. These are considerable: both the Vatican and its leader have immunity from civil or criminal actions for the damage that they do to others - whether by trafficking paedophile priests or by condoning fraud at the Vatican Bank (suspects can avoid European arrest warrants by staying within the "inviolable" walls of the Holy City).
At the UN, which has wrongly allowed the Holy See to do everything a nation state may do except vote in the General Assembly (where it is nonetheless accorded six seats from which to speak and lobby), the Church's advantages over other faith groups are enormous. At conferences, it lobbies relentlessly (usually with the help of Libya and Iraq) against any humanitarian action that might condone the "heinous evils" of abortion - even after incest or rape - or homosexuality, and attempts to sabotage the distribution of condoms, including to married couples, to contain the plague of HIV/Aids.
At meetings to settle agendas relating to UN conferences on social or economic issues, Holy See diplomats have been exploiting their "statehood" to oppose the inclusion of any language that sends a shudder up their spiritual spine - "gender" and "gender equality", "sexual orientation", "unwanted pregnancy", "unsafe abortion", "sex education", "reproductive health", "reproductive rights", "contraception", "sexual health", "couples and individuals" and even "lifestyle". Sovereign statehood brings huge advantages over other faith groups and non-governmental organisations, which the Church uses to oppose the sexual and health rights of everyone and the rights of women in particular.
But this is not the only illegitimate consequence of regarding Vatican City - or its government, the Holy See - as a state. As part of its "sovereignty", the Vatican claims the right, in all states where its Church operates, to deal with its priests and other "religious" under canon law - the set of ecclesiastical rules that includes disciplinary provisions for offences ranging from ordaining women and promoting heresy to having sex with children.
While there can be no objection to an organisation disciplining members for a breach of arcane rules, there is every objection when those breaches amount to serious crimes and the organisation claims the right to deal with them internally without reporting them to the police. And that is precisely what the Vatican has been doing: instead of reporting to the law-enforcement authorities those priests whom it knows to be guilty of raping children, and to be likely to rape more children in the future, it has been dealing with them under canon law, which demands utmost "pontifical" secrecy, moving them to other parishes and other countries and letting them off with admonitions and unenforceable "penances" (usually to say prayers for their victims).
On occasion, they are accorded a canon law "trial" under a medieval written procedure run by fellow priests, which permits neither cross-examination and medical examination nor DNA testing. In the unlikely event that the trial ends in conviction, canon law has no "punishment" worthy of that name. The worst that can happen, other than an order to do penance, is "laicisation" - that is, defrocking - which permits the paedophile to leave the Church and get a job in a state school or care home without anyone knowing of this "conviction". Canon law has no sex offenders' register.
It is the Vatican's obsessive attachment to its right to deal with clerical sex abuse of children under the secrecy of canon law procedures, without permitting (let alone requiring) any reporting of the crime or the criminal to law-enforcement agencies, that has been central to its present crisis.
It is now clear that tens of thousands - perhaps even approaching 100,000 - children, mainly boys, were sexually molested by priests over a period (1981-2005) coinciding with Cardinal Ratzinger's responsibility as head "prefect" of the Congregation for the Doctrine of the Faith (the CDF, the Vatican body that oversees canon law proceedings against them). Judicial inquiries have described sexual abuse as "endemic" in Catholic boys' homes in Ireland. The report of the understated John Jay College inquiry, published in 2004, found 10,667 victims in the US, where over $1.6bn is believed to have been paid in damages so far. A truth commission in Canada is uncovering huge abuse in Catholic-run residential homes. In Melbourne, Australia, the Church has had to compensate 300 victims of 60 molesting priests, only one of whom it has defrocked. Forty-five of Malta's 850 priests are suspected paedophiles, with multiple victims. Similar incidents are emerging from the priesthood in Austria, Belgium and Germany. It is said that the scale of sex abuse in Latin America and Africa, to which many paedophile priests from America and Europe have been trafficked, will be even worse.
Abuse happened on this scale - and was allowed to happen - in part because Joseph Ratzinger, both as head of the CDF and as Pope, has insisted for the past 30 years that all such cases be dealt with in secrecy under canon law. As late as July this year, when he promulgated new canon laws about sex abuse (finally making it as serious an offence as ordaining a woman), he deliberately and adamantly refused to direct his bishops to report confirmed or reasonably suspected cases of child rape to the police.
How on earth do these statehood privileges, extending even to the power to use its own law to the exclusion of local criminal law, come to be vouchsafed to just one out of many religions and NGOs? To qualify as a state in international law, an entity must have territory and must have people - a permanent population.
As any tourist in St Peter's Square will recognise, Vatican City has neither. It is simply a palace with a large basilica and ample gardens, less than a quarter of a square mile in size, like so many golf courses. It has no "Vaticanians", just a few hundred celibate Catholic bureaucrats and some daily workers who come over the road from Italy. It is a palace with museums but no nationals; all its basic services are provided from Italy.
The Holy See lacks any stable human society. Its only "permanent" member is the pontiff, who prefers on many evenings to pope-copter off to his residence in Italy, Castel Gandolfo. He has no "people" to enter in the Olympics or to play in the World Cup or to serve on any international peacekeeping mission: even the papal guards are Swiss. In reality, Vaticanland is no more a state than Bophuthatswana, or indeed Disneyland - which is larger than the Vatican and has more denizens, dressed in even more colourful costumes.
So, why does Britain recognise the Vatican as a state when it so obviously is not? I have recently asked this question through Freedom of Information requests, and have been told by the Foreign Office that it does so in reliance on the Lateran Treaty of 1929. The Holy See itself bases its claim to statehood squarely on this document. But the Lateran Treaty was a squalid deal to secure fascism in Italy, negotiated between Benito Mussolini and Pope Pius XI, who hailed the demagogue as "the man sent by providence" to put an end to liberal democracy. In truth, it was not a "treaty" - a written agreement between states - at all, but a deal between one state and its Church, as the Holy See had lost any claim to statehood after its territory (the papal states) was conquered by the army of the Risorgimento in 1870.
Nonetheless, in return for electoral support, Mussolini conveyed the patch of land containing the Vatican Palace and gardens to the pope to provide him with some territory to assist his claim to statehood, which papal diplomats said was needed in order to promote his religion's "mission to the world". Although states with Catholic populations soon sent envoys, only 85 countries had any diplomatic connections until the Reagan administration recognised the advantage of having a head of state who was profoundly anti-communist, and many western states followed when the US recognised the Holy See in 1984. Some of them opened embassies to the Vatican (located in Italy) and received papal nuncios (most of whom are still Italian) in return.
But that the Holy See is capable of having diplomatic relations with other states does not necessarily prove that it is a state itself, and some international lawyers have pointed out that it lacks people, territory and other qualifications necessary to be judged objectively as a state in international law. If they are right, the Pope would not be "head" of a state and could be sued for the negligence in relation to the traffic in paedophile priests, which happened on his watch over the 24 years when he ran the CDF.
The Lateran "treaty", for all its unsavoury fascist origins, is accorded the most astounding (and legally mistaken) respect by the Foreign Office. To a Freedom of Information request made on my behalf, asking why it was necessary for the British taxpayer to fund two separate embassies in Rome, one to the Vatican and one to Italy, the response (which came from "the Assistant Desk Officer, Papal Visit Team") was that "under the Lateran Pact, it is impossible for a state to merge its embassies to Italy with the Holy See . . . they are in separate buildings . . . in accordance with the Lateran Pacts, the two ambassadors' residences remain located in separate parts of Rome".
It is nonsense to claim that there is anything in the Lateran Treaty that requires this separation, and acceptance of the Vatican bluff that it does has cost the UK millions of euros over the years. Our superfluous embassy to the Vatican performs no useful or consular service for UK citizens. When I rang its doorbell recently during office hours, I was informed that visits were by appointment only. When I claimed to have had my passport stolen in the Sistine Chapel (an increasingly common experience), I was referred to the UK's embassy to Italy. It is astonishing that the Foreign Office has been such a pushover, conceding a claim by Vatican diplomats that is not only wrong in law but based on a treaty to which the UK is not a party. And, speaking of parties, the UK's Vatican embassy hosted 52 of them (one a week) in 2008 for 1,338 guests, namely "senior Vatican officials and others connected with Holy See diplomacy". It is unlikely that the conversations over champagne and canapés raised questions about Vatican accountability for sexual abuse of children, or deaths from condom-preventable HIV/Aids.
Reliance on the Lateran pact, which is not a treaty and to which Britain is not in any event a party, is ironic, given its Article 24, which makes the Pope's sovereignty conditional on his abjuring any part in "temporal rivalries". Recent popes have reneged on this undertaking - in 1999, with the approval of Pope John Paul II, the then Vatican secretary of state, Cardinal Sodano, launched a ferocious public attack on the UK for daring to detain General Augusto Pinochet; this year, Benedict XVI condemned the UK's Equality Bill and urged his bishops to fight it "with missionary zeal".
While head of the CDF, the Pope formulated a plan to put pressure on Catholic politicians in all democratic countries to vote against abortion in any circumstances (even to save the life of the mother) and to use their political power to prevent laws providing for gay marriage.
If they contravene the Church teachings, they are to be excluded from Mass, and possibly excommunicated. Under his present Vatican "enforcer", the American archbishop Raymond Burke (who led a campaign to exclude John Kerry from Mass when he was running against George W Bush), the same threats are being made against Vice-President Joe Biden and Nancy Pelosi, Democratic leader in the House of Representatives. The exercise by one state of power to use spiritual blackmail against democratically elected politicians in other states is a fundamental breach of Article 24 of the very "treaty" under which the Vatican claims to be a state. So, too, is its use of canon law to harbour those who have committed serious crimes.
In that respect, it is astonishing that the Holy See has escaped examination by human rights bodies and the UN. It has ratified only two human rights treaties - the Convention against Torture (it has a curious reservation that seems to provide an exemption for torture in hell), and the Convention on the Rights of the Child. The latter treaty (endorsed almost unanimously) imposes the "paramountcy principle" that the interests of the child must always come first. There is now overwhelming evidence that the Vatican and its leader have consistently and inexcusably breached the children's convention, preferring to cover up clerical sex abuse of children in the interests of protecting the reputation and wealth of the Catholic Church. The UN's ineffectual "committee of experts", which pretends to supervise compliance with the convention, has said not a word.
What is most astonishing about Vatican "statehood" is that it has avoided criticism. It refuses to ratify most human rights treaties (even China has a better record in this respect). It uses its privileged platform at the UN to oppose equal and decent treatment for women and gay people; it opposes reproductive rights of all kinds, not to mention divorce, embryo experimentation, IVF and artificial insemination (because the sperm is obtained from masturbation), any form of artificial contraception and even prenatal scans. Not only is it hostile to many human rights, it is responsible for covering up the widespread and systematic molestation of children by its own officials and servants. There has not been a whisper of criticism from Amnesty International, or Human Rights Watch, or from nations such as the UK which claim to be concerned about human rights violations by other states.
One reason is that no political leader is prepared to alienate Catholic voters by criticising the Pope: Tony Blair went four times to kiss the Fisherman's Ring, while Vladimir Putin visited three times as president, as did George Bush during just his first term. A more acceptable reason is that the Vatican has a degree of protection within human rights circles because of the outstanding work being done by Cafod, Caritas and other Catholic charities, especially in remote impoverished areas of Africa and Asia. This is the splendid side of a church which brings joy and faith into the lives of hundreds of millions of adherents and cares with genuine compassion for the poor and the sick.
As head of that Church, Benedict XVI should be welcomed enthusiastically to Britain. But watch out whenever he wears his opulent robes of statehood, and look at him through the eyes of the thousands of small boys who have been bewitched, buggered and bewildered by priests protected under canon law.
Geoffrey Robertson, QC is the author of "Cases Against Humanity". His new book, "The Case of the Pope: Vatican Accountability for Human Rights Abuse", is published on 8 September as a Penguin Special (£5.99)