A Popemobile stained with rotting aubergines. A papal convoy protected by low-flying military helicopters and battalions of gun-toting special agents. Call them reasonable predictions for Pope Benedict's visit to the UK in September, but could he really be detained by British police?

Arresting the Pope for crimes against humanity may seem a pipe dream, yet it's possible, if scientist Richard Dawkins and writer Christopher Hitchens prove the case. They believe they will. The alleged criminal complicity in covering up systematic child sex abuse is being investigated by various networks worldwide. The grounds for immunity against being prosecuted for them are being queried by senior British legal experts, Geoffrey Robertson QC and Mark Stephens.

Dawkins and Hitchens want the immunity grounds removed so that Benedict can be arrested and charged once he sets foot in Britain. Some say the demand is a headline-grabbing stunt, yet its intricacies question the Vatican's claim for diplomatic immunity against child abuse and other prosecutions worldwide.

Equality before the law is such a basic assumption that people go about their everyday life thinking state authorities don't make exceptions, especially in criminal cases and when children are at stake. Or did, until they heard rollercoaster revelations about the Vatican's role in relation to child abuse in Ireland, Germany, Italy and the US.

Benedict is implicated both as Pope and, especially, for what he did or didn't do as head of the Congregation for the Doctrine of the Faith. Hitchens argues that it's a matter of conduct, not religious belief -- which addresses the Vatican press office's claims that atheists and agnostics are on a crusade against the Catholic Church. Why should a priest anywhere be above civil law, he asked?

Dawkins calls Benedict "grotesquely tainted". For many reasons, there's a great gap between Benedict condemning the Irish hierarchy's "grave errors of judgment" and his almost contemptuous refusal to discuss his role in handling abuse cases at Wisconsin, Munich and Oakland, California. Why should he not answer legitimate questions in a civil court?

The questions are legion. For example: As Cardinal Ratzinger, Benedict overruled a local bishop in California who wanted 38-year-old Fr Stephen Kiesle defrocked. Kiesle tied up and raped Catholic boys aged 11 to 13, among other offences. Ratzinger saw the issue differently.

"This (church) court, although it regards the arguments presented in favour of removal in this case to be of grave significance, nevertheless deems it necessary to consider the good of the universal church together with that of the petitioner," he wrote in Latin, "and it is also unable to make light of the detriment that granting the dispensation can provoke with the community of Christ's faithful, particularly regarding the young age of the petitioner."

Extraordinary stuff. The 'young age' mentioned is the 38-year old, not the children he attacked. If the man were defrocked, Ratzinger's reasoning goes, lay people would be alerted to the crime and their faith in the church could be damaged. So would the church's moral authority.

Despite the worldwide furore, and decades of (mis)managing abuse, the Vatican waited until Monday of this week to change its standing order about reporting to church rather than civil authorities. That amounts to years of flaunting its alleged status as a separate state, entitled to enforcing its own laws elsewhere because of diplomatic immunity.

The history bit goes back to a deal done between the dictator Benito Mussolini and Pius XI in 1929, where Mussolini recognised a new independent Vatican City State, in exchange for Pius relinquishing claims to other Italian territories.

Mussolini paid hefty compensation and gave the Vatican control of marriage and family law. In return, Pius XI effectively enabled Mussolini to consolidate his political power and go on to make alliances with Adolf Hitler. Pius invested the money and grew the Vatican bank.

Robertson and Stephens, the British lawyers, believe the Mussolini-Pius deal was a piece of ad-hockery that is suspect under international law. If/when they prove it, the Vatican's special status at the UN will come into question, diminishing its claims to be a state like any other. Smoke and mirrors, rather than built on rock.

It's uncanny how the Vatican State straddles both sides of the maxim about giving separately to Caesar and to God, secular and sacred. US Catholics, always more vocal, are opening another flank in the campaign against clerical child abusers by calling for an independent commission to examine the problems, make recommendations and open the way for a Vatican III.

The push for change is coming within and without the Catholic Church. Despite all that, one of the Vatican's most recent initiatives is to order an investigation of every American order of nuns in case they are straying from CDF guidelines. Practising reiki is on the charge list. Cynics might wonder why the Vatican is trying to keep religious women in check but no doubt the CDF has its own reasons. What they are is quite a mystery.

Paddy Powers would scoff at the odds of PM Cameron or Brown having Benedict arrested in Britain but he certainly won't get the welcome John Paul II did 28 years ago. Leave the last words to Bob Dylan, as Sinead O'Connor interpreted them so truthfully on The Late Late Show. "Your sons and your daughters are beyond your command, your old road is rapidly agin', Please get out of the new one if you can't lend your hand. For the times they are a-changin'."

Irish Independent