The parents of Madeleine McCann have talked for the first time about the prospect of never seeing their daughter again as the search for a possible burial site was called off by Portuguese police yesterday.

The couple said they were relieved that the police had failed to find any trace of their daughter during the search of remote scrubland about nine miles from where she was abducted from her bed 43 days ago.

Mr and Mrs McCann, who have drawn heavily on their Catholic faith since their daughter’s abduction, said that although they were convinced Madeleine, 4, was still alive, they had considered what would happen if she were not returned home.

Gerry McCann, 39, said: “If we don’t get Madeleine back alive and well, I am sure our faith will be severely tested. At the end of it, we will still have our faith and we will also have comfort that Madeleine will be looked after.

 “We haven’t dwelt on that, but I think that is what we will be left with. Our friends, our family, the Church have really rallied round. I think that’s the key thing for me,” he told The Tablet, a Catholic newspaper.

His wife Kate, a 38-year-old locum GP, said: “I have considered that as well and I have felt guilty asking, ‘Will this make or break my faith?’. And yet, at the same time you could argue that what’s happened in the first place could make or break your faith, and it hasn’t. It’s done the opposite. It has given us hope and strength.”

Mr McCann said that in the first few days they had feared that Madeleine, 4, was dead, until the arrival of two trauma specialists, Alan Pike and Martin Alderton, from the Centre for Crisis Psychology in Skipton, North Yorkshire.

“We couldn’t get out of our heads that she was likely to be dead, and we were truly, truly grieving,” Mr McCann said.

“But then the psychologist said: ‘Is there any other possibility?’ And then he started channelling negatives and saying: ‘Of course there are other possibilities.’ And we started to see that.”

The couple, from Rothley, Leicestershire, have regularly attended the church of Nossa Senhora da Luz (Our Lady of Light) in Praia da Luz for Mass and have been given the keys to the building to pray privately in the evenings. Mr McCann, whose faith had lapsed for a time when he was in his twenties, told The Tablet about an experience he had while praying in the church during the days after Madeleine disappeared.

“When I was praying, I started thinking of all the things that were happening. There were lots of ideas in my head of how we could make things better and I was really feeling very down and not sure which way to proceed,” said Mr McCann.

“I had this mental image of being in a tunnel and instead of the light at the end of the tunnel being extremely narrow and a distant spot, the light opened up and the tunnel got wider and wider and went in many different directions.

“I talked to you [Kate] about it and said, ‘I am not prepared to pursue one path. We are going to do everything in our power to influence things’. It was almost like something — I am not saying it was the Holy Spirit — came into me and gave me that image. That is when I really felt I had a clear path.”

The couple have led a campaign to find their daughter that has included meeting Pope Benedict

XVI and trips to Madrid, Berlin, Amsterdam and Rabat to promote the international search for Madeleine.

Meanwhile, the police have been forced to follow a series of false leads across the world, including the latest tip-off from the Netherlands.