Pope Benedict XVI has said young people desire to know God in a world filled with superficiality, consumerism, and the “widespread banalisation of sexuality”.

Speaking at the start of his four-day visit to Madrid on Wednesday, the Pope said the reason so many young people had gathered in the Spanish capital was because they “wish to hear the Word of God” and “manifest the strength of their faith”.

Up to one million Catholic youths are in the city for World Youth Day, the Catholic Church’s international youth festival which takes place every three years.

“Many of them have heard the voice of God, perhaps only as a little whisper, which has led them to search for him more diligently and to share with others the experience of the force which he has in their lives," he said.

“The discovery of the living God inspires young people and opens their eyes to the challenges of the world in which they live, with its possibilities and limitations.

"They see the prevailing superficiality, consumerism and hedonism, the widespread banalisation of sexuality, the lack of solidarity, the corruption.

“They know that, without God, it would be hard to confront these challenges and to be truly happy, and thus pouring out their enthusiasm in the attainment of an authentic life."

The Pope encouraged young Catholics to entrust themselves completely to Christ and know that they are “not alone”.

He said that seeing so many participants in World Youth Day filled him with confidence about the future of the Church.

“Of course, there is no lack of difficulties,” he continued. “There are tensions and ongoing conflicts all over the world, even to the shedding of blood.

“But, with all my heart I say again to you young people: let nothing and no one take away your peace. Do not be ashamed of the Lord.

“He did not spare himself in becoming one like us and in experiencing our anguish so as to lift it up to God, and in this way he saved us."

The Pope was welcomed to Spain by King Juan Carlos I, who made reference to the economic difficulties that have sparked protests over the cost of the Pope’s visit to Spanish taxpayers.

“All of those who have come to Madrid await your teachings of peace, charity and justice to shape their lives, successfully face today’s challenges and build a better society,” the King said.

“These are not easy times for young people, so often frustrated by the lack of personal horizons and jobs at the same time as they rebel against the grave problems that burden humanity and today’s world.”

Around 4,000 pilgrims from the UK are attending World Youth Day, accompanied by the head of the Roman Catholic Church in England and Wales, Archbishop Vincent Nichols.

The event culminates on Sunday with an open-air mass led by the Pope.