Madeleine McCann's parents received hate mail blaming their "drunken arrogance" for her disappearance in Portugal a year ago, they said in a television interview to be shown on Wednesday.

Kate and Gerry McCann said they were inundated with messages of support, as well as letters from psychics, conspiracy theorists and people who thought they should not have left their children alone.

Gerry McCann read out a letter which said: "Your brat is dead because of your drunken arrogance. Shame on you. I curse you and your family to suffer forever."

They had so many letters that they began filing them in cardboard boxes marked with labels such as "Nasty", "Nutty" and "Psychics, Visions, Dreams".

The year since Madeleine disappeared on May 3 while on holiday in southern Portugal had been like "a horror movie", Gerry McCann said.

In a wide-ranging interview with ITV, he said he feared they would be sent to prison after Portuguese police made them official suspects in the case.

"The speculation takes you to the worst places and at that point you know the worst place would have been being charged, potentially being put in jail," he said, according to transcripts released by ITV.

Kate McCann said she was afraid that the authorities might take away her twins, Amelie and Sean. She asked her family to make sure they were safe.

"I can remember saying to Gerry's mum and Gerry's sisters, 'do not let anyone near them'," she said. "You know I'd just do whatever it took to protect them."

The couple described why they decided to leave their children asleep in their holiday apartment while they ate with friends at a nearby restaurant.

"It seemed a fairly natural sort of thing to do, it was so close," Gerry McCann said. "You could actually see the apartment and it didn't feel that different to dining out in the back garden. It was the furthest thing from my mind that something like that might happen."

He added: "We have to live with the fact that we weren't directly there and if we were then you know possibly, probably it wouldn't have happened."

The day before her disappearance, Madeleine asked her mother why they hadn't come to her when she and one of the twins were crying.

Kate McCann said: "She just very casually said 'where were you last night when me and Sean cried?'. And then she just carried on playing, totally undistressed."

The McCanns said they still hold out hope that their daughter is alive.

"I feel more positive about the chances of Madeleine being out there," Kate McCann said.