'You have challenged the nation to sit up and think'

However Mr Cameron also addressed the Pope's attacks on "aggressive secularism", defending the country by emphasising its record for "compassion".

He told the Pope: "Your Holiness, on this truly historic first state visit to Britain you have spoken to a nation of six million Catholics but you have been heard by a nation of more than 60 million citizens and by many millions more all around the world. For you have offered a message not just to the Catholic Church but to each and every one of us of every faith and none.

"It is a challenge to us all to follow our conscience, to ask not what are my entitlements, but what are my responsibilities, to ask not what we can do for ourselves, but what we can do for others."

Mr Cameron drew on the message of Cardinal John Henry Newman who was beatified at a Mass in Cofton Park, Birmingham, saying the "common bond of unity" that we all share is "at the heart of the new culture of social responsibility that we want to build in Britain".

The Pope's message has, at times, been an uncomfortable one for politicians, speaking out against what he called "aggressive secularism" and warning against the "marginalisation" of Christianity in modern Britain.

But Mr Cameron told the pontiff he agreed with him about the importance of religious faith in public life.

He said: "Faith is part of the fabric of our country. It always has been and it always will be. As you, your Holiness, have said, faith is not a problem for legislators to solve but rather a vital part of our national conversation. And we are proud of that."

Mr Cameron said people did not have to share religious faith to ask questions about "our society and how we treat ourselves and each other".

He continued: "You have really challenged the whole country to sit up and think, and that can only be a good thing."

The Prime Minister said he had agreed to co-operate with the Holy See on international issues such as climate change.