"The most important things you can do is keep her face out there … but you can never give up hope because you know she could be out there and the things that you're doing today could bring her home."
Most recently, while the McCanns made a plea for a child alert system to be established in Europe, sealed statements the couple made to Portuguese police just after Madeleine disappeared were leaked to the press.
According to the leaked statements, on the morning of their last day together, Madeleine asked Kate, "Mummy, why didn't you come when we were crying last night?"
The McCanns say the leak is no accident and is meant to make them look negligent. Portuguese police deny any responsibility for the leak but the McCanns feel the damage has been done -- once again, doubts are cast about their behavior.
Kate believes Madeleine's question was a potential clue.
"It was sort of fairly early in the morning, she just very casually really said, 'Where were you last night when me and Sean cried?' and we immediately looked and said, you know, 'When was this Madeleine? Was this when you were going to sleep?' … and she didn't answer and I said, 'When was this Madeleine?' and then she just carried on playing whatever she was doing totally undistressed."
Kate said, "It doesn't feel like a year since I saw Madeleine. I see Madeleine's best friend from time to time and you can't help but wonder what Madeleine would be like, would she be that much taller, is her hair as long as that, would she be writing her name too? She's there waiting for us, and she deserves us to keep going."
For more information on Madeleine McCann: http://www.findmadeleine.com/