Pope Benedict XVI inspects a guard of honour accompanied by Britain's Prince Philip at Edinburgh airport, September 16, 2010. STORY HIGHLIGHTS- Pope: The church has not been vigilant or fast enough to respond
- He describes "sadness" and says the abuse is difficult to understand
- The pope is visiting England and Scotland for four days
- It is the first state-visit by a pope to Britain
London, England (CNN) -- Pope Benedict XVI said Thursday the Roman Catholic Church has not been vigilant enough or fast enough in responding to the problem of sexual abuse by priests.
"These revelations were for me a shock and a great sadness. It is difficult to understand how this perversion of the priestly ministry was possible," he told reporters aboard his plane to Scotland, according to the Catholic News Service (CNS), which was with him on the plane.
Asked about the sexual abuse, the pope said it was inexplicable to him how a priest who has promised at his ordination to act in the person of Christ, as a good shepherd, could "fall into this perversion," CNS reported.
"It is a great sadness. It is a sadness, also, that the authority of the church was not vigilant enough, was not sufficiently fast and decisive in taking the necessary measures," he said.
The pope made the comments as he arrived for a historic four-day state visit to Britain, where the issue of abuse, and the Vatican's perceived lack of response to it, has created anger.
Britain's Queen Elizabeth II shook hands with the pope as he arrived Thursday at her Scottish residence near Edinburgh, the Palace of Holyroodhouse, before they sat down for a private meeting. A military marching band played the national anthem God Save the Queen, for which the pope removed his white cap.
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- Pope Benedict XVI
Earlier, as the pope arrived at the Edinburgh airport in an Alitalia plane, a Union Jack and Vatican City flag were flown out of the cockpit windows.
Prince Philip, the queen's husband, greeted the pope as he stepped off the plane, according to royal protocol for a state visit. It was a sunny but windy day in Edinburgh, and as the pope walked off the tarmac, his cape briefly blew in his face and he had to brush it away.
The pope used relatively strong language in a speech delivered after the meeting with the queen, reflecting on the "sobering lessons of the atheist extremism" of the 20th century.
He reminded the media of its "greater responsibility than most" to promote peace and the spread of human rights, and he reminded the country of its "deep Christian roots" that he said are still present in "every layer" of British life.
"Today, the United Kingdom strives to be a modern and multicultural society," the pope said. "In this challenging enterprise, may it always maintain its respect for those traditional values and cultural expressions that more aggressive forms of secularism no longer value or even tolerate. Let it not obscure the Christian foundation that underpins its freedoms."
Thousands of people, including bagpipe players and marching bands, stood along Edinburgh's famous Princes Street afterward to watch the pope ride by in his popemobile.
A huge security operation was being mounted to protect the pope during the trip -- the first papal state visit to Britain -- bumping estimated costs beyond 20 million pounds ($31 million), with more than half coming from the British government.
Thousands were expected to greet Benedict at public Masses in Glasgow, Birmingham, and London and on the sidelines of meetings with political leaders, royalty and bridge-building events with Anglican Church officials.
Benedict's September 16-19 trip is scheduled to culminate in the beatification of British Cardinal John Henry Newman, a Catholic convert who died in 1890 and is credited with helping rebuild Britain's Catholic community.
But with apathy and anger denting the U.K.'s Catholic following -- estimated at 9 percent of the population -- the atmosphere greeting Benedict was expected to be very different from festivities that met a pastoral visit 28 years ago by his predecessor, John Paul II.
Later in the day, the pope was to move on to Glasgow, where he planned a Mass at Bellahouston Park.
Assistant Chief Constable Fiona Taylor, of Scotland's Strathclyde Police, said earlier this week that she estimated only 65,000 pilgrims would attend the pope's Glasgow Mass -- short of an initially anticipated 100,000.
There has already been widespread outcry over the estimated 12 million pounds ($18.7 million) British taxpayers are having to pay for the visit, though Christopher Patten, the prime minister's representative for the papal visit, has pointed out that one day of last year's G-20 summit in London cost 20 million pounds.
Criticism has also focused on the armed police squads needed to protect a religious figurehead previously targeted by attackers.
South Yorkshire Police Chief Constable Meredydd Hughes, who is coordinating security for the English leg of the trip, has estimated the policing bill alone could top 1.5 million pounds ($2.3 million).
The Association of Chief Police Officers insists the figure is a very rough estimate and doesn't take into account the reallocation of existing resources or the cost of policing the Scottish section.
Scottish police have already revealed they will deploy 1,600 officers, backed by armed units, to protect the pope. The pontiff's own personal guard will not carry weapons.
More than 60 bridges will be closed temporarily when his 15-vehicle convoy travels from Edinburgh to Glasgow.
Police say some of the measures are being taken as a precaution against possible protests from Protestant groups who maintain a vocal presence in Glasgow.
Hughes said police operations in England will ensure the "safety and dignity of the pope" while also protecting both his followers and protesters. He said there was no intelligence to suggest a specific threat against Benedict.
The pope is also expected to be dogged by anger over a child abuse scandal. Benedict has apologized for abuse perpetrated by priests in several Catholic communities around the world, but has faced criticism over the Vatican's handling of the issue.
Others in Britain have questioned why the pope has been accorded a state visit given his and the Catholic Church's attitudes towards gender equality and homosexuality.
"We object to the British government honoring him with a state visit -- we do not think he deserves it," said human rights campaigner Peter Tatchell, a spokesman for the group Protest the Pope.
"We also object to the fact that this visit has been funded by the taxpayer at the public expense," Tatchell told CNN. "We do not as a country fund visits by the grand mufti of Mecca, or the chief rabbi of Jerusalem, so why should the pope's visit receive privileged financial support?"
Tatchell described Protest the Pope as "a coalition of Catholics and non-Catholics united in our opposition to the pope's often harsh, intolerant teachings."
A letter published in the Guardian newspaper, jointly signed by popular authors Terry Pratchett and Philip Pullman, scientist Richard Dawkins, and other British celebrities, also criticized the visit, chiefly over the Vatican's views on birth control, gay rights and abortion.
Catholic leaders and government officials have sought to defend the trip.
In a recorded video message, Prime Minister David Cameron said Britain and the Holy See had "incredibly important work to do together" in promoting a "multi-faith dialogue."
"Not everyone will agree with everything the pope says, but that should not prevent us from acknowledging that the pope's broader message can help challenge us to ask searching questions about our society and how we treat ourselves and each other," he said.
Patten told CNN the government was "delighted" by the visit and regards it as an "extremely special moment."
Archbishop Vincent Nichols, president of the Catholic Bishops' Conference of England and Wales, says the trip will be justified by landmark events that will help forge stronger ties between the Catholic and Anglican communities.
Among these will be meetings with the queen, the nominal head of the Anglican Church, joint prayers with the Archbishop of Canterbury, and the first visit by a pope to the archbishop's Lambeth Palace residence.
Nichols has also indicated that the pope will likely hold private meetings with victims of child abuse during his visit, but said he hopes the issue will not "overshadow" the visit.