A historic day, a stirring appeal, but can the Pope escape the abuse scandal?

Pope Benedict XVI began his four-day state visit to Britain yesterday with a frank admission that the Church was too slow in tackling clerical sex abuse and a warning that the UK should resist "aggressive forms of secularism" which threaten to undermine the country's "Christian foundations".

Even before flight AZ4000 – dubbed "Shepherd One" – landed in Scotland yesterday morning, the 83-year-old pontiff made it clear that he would not shy away from controversy or difficult subjects during the first state visit to Britain by a pope.

He told reporters on board the plane that Church leaders had been "insufficiently vigilant" in halting the sexual abuse of children. "It is difficult to understand how this perversion of the priestly ministry was possible," said the Pope, who once led the Vatican council charged with investigating crimes of priests. "It is also a great sadness that the authority of the Church was not sufficiently vigilant and not sufficiently quick and decisive in taking the necessary measures."

At Edinburgh airport plans for a red carpet had to be scrapped because of a strong breeze. The Pope was met by senior Catholic officials and the Duke of Edinburgh before being driven Holyroodhouse to greet the Queen. After a brief exchange of gifts and a private meeting over glasses of fizzy water and squash, the two sovereigns stepped outside for welcome speeches where the Pope lost no time in setting out his agenda for the visit.

"Today, the United Kingdom strives to be a modern and multicultural society," the pontiff said in his opening speech, delivered just days after a Vatican cardinal likened Britain to a "Third World" nation. "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."

He paid tribute to the country's "Christian roots", praising saints like Edward the Confessor and Margaret of Scotland and lauding British Christianity's role in putting an end to the slave trade.

"Even in our own lifetime," he added, "we can recall how Britain and her leaders stood against a Nazi tyranny that wished to eradicate God from society and denied our common humanity to many, especially the Jews, who were thought unfit to live."

The Queen, meanwhile, praised the Catholic's Church's "special contribution" towards helping the poor and needy around the world.

"We know from experience that through committed dialogue, old suspicions can be transcended and a greater mutual trust encouraged," she said. "We hold that freedom to worship is at the core of our tolerant and democratic society."

The only shadow cast over the meticulous planning and pageantry of the Pope's meeting with the Queen came when the Rev John Christie, the Moderator of the Church of Scotland, was mistakenly left out of the welcoming committee at Holyrood. He was later granted a private audience.

The Pope's attack on "aggressive secularism" immediately drew fire from campaigners. Andrew Copson, chief executive of the British Humanist Association, said: "The notion that it is non-religious people in the UK today who want to force their views on others, coming from a man whose organisation exerts itself internationally to impose its narrow and exclusive form of morality and undermine the human rights of women, children, gay people and many others is surreal."

His comments on clerical paedophilia also did little to mollify abuse survivors. Margaret Kennedy, founder of Ministry and Clergy Sexual Abuse Survivors, said: "Far from being a misdemeanour of tardiness, the policy of moving clergy, putting them in new dioceses and new countries was a worldwide strategy rather than sloppy action. In this regard the Vatican and Church leaders can be accused of grave neglect, sinful and criminal disregard of the normal human instinct to safeguard children and blatant disregard of adult survivors who reported and warned of the dangers."

But as the pontiff made his way through the streets of Edinburgh in his bullet-proof Popemobile – a tartan scarf given to him by Cardinal Keith O'Brien draped on his shoulder – the small group of protesters gathered at the side of Princes Street was drowned out by what police estimated was a crowd of some 125,000 flag-waving supporters. Sister Francis, from the Carmelite Monastery in Fife, said: "I'm very excited and very privileged to be able to come and welcome and support him."

After lunch, the Pope was driven along a closed-off M8 to Glasgow's Bellahouston Park for the first of three open air Masses. In front of a crowd of some 65,000 he warned against secularism and the "dictatorship of relativism" – a term coined by Benedict to describe the way modern societies tend to pick and choose which morals and teachings they adhere to.

"There are some who now seek to exclude religious belief from public discourse, to privatise it or even paint it as a threat to equality and liberty," he said. "Yet religion is in fact a guarantee of authentic liberty and respect, leading us to look upon every person as a brother or a sister."

Royal gaffe: From the hand of friendship to the foot in the mouth

The Prince isn't losing his touch:

It was a historic day for both papacy and monarchy: the first official state visit to Britain by a pope since Henry VIII's matrimonial entanglements became even more complicated than those of the current Queen's offspring. But no sooner had the infallible pontiff extended the "hand of friendship" at Holyrood yesterday than our own decidedly fallible Duke of Edinburgh struck, as he has so many times.

The Pope had been welcomed to the UK by the Queen and Prince Philip at the Palace of Holyroodhouse, after which the trio were introduced to dignitaries at an official reception.

The Prince soon became involved in a conversation with the Scottish Labour leader, Iain Gray, who was sporting a special papal tartan tie, and the Scottish Conservative leader, Annabel Goldie. "Have you got a pair of knickers made out of this?" the Duke inquired of Ms Goldie, adding another fine specimen to his collection of inappropriate remarks.

"I couldn't possibly comment – and even if I did, I couldn't possibly exhibit them," Ms Goldie replied gamely.

A friend of the unfortunate politician claimed that she was in "hoots of laughter" over the exchange. "It's marvellous to know that humour is alive and well in the Royal Family," they said.