Family and friends of a Baildon man who went missing in Amsterdam a month ago today said they were determined to keep up the search.

Ian Walton, 36, was last seen on Saturday, December 20, while on a pre-Christmas break with friends in the Dutch capital.

His parents Laurie and Margaret Walton said they were determined not to give up hope that he was still alive.

"We have to remain as positive as we can because as long as we don't know what happened, he could still be out there," said Mrs Walton, of North Ferriby, East Yorkshire. "Part of me thinks maybe he wanted a bit of time out or to start a new life, but we just don't know.

"We received the Christmas present for his dad the other day - a sound system for his DVD player, but we don't know how it works. Ian's a sound engineer - he has to come back so we can set it up.

"All his friends in Bradford are missing him and praying for him."

Mr Walton's friends Roger and Michael Dyer returned from Amsterdam on Friday after the latest of three trips to hunt for him.

The brothers spent the day putting up posters and checking hostels, but the search proved fruitless.

Roger, 34, of Walker Wood, Baildon, said: "It's been a month now, but we're remaining positive and we'll keep trying.

"If we hear nothing over the next few weeks, we'll go back again."

Mr Walton, of West Lane, Baildon, worked as a shower installer and is a qualified joiner, shop fitter and sound engineer.

Friends said he was acting normally on the night of his disappearance.

Ian Shackleton, who was with Mr Walton and another friend Paul Holmes in Amsterdam on the night he disappeared, said: "He was just as he would have been on any night out in Bradford.

"It would be totally out of character for him to disappear without telling his family and friends."

Mr Walton's former partner Janice Weldon said: "We're still keeping positive because no news is good news.

"We're all doing our best to support each other."

Amsterdam police are continuing their search of the city's network of canals.

Detective Max Eman said a television appeal was due to be broadcast tomorrow.

He said several people came forward after a previous televised appeal, but were unable to offer any clues.

"We are still searching but Amsterdam is a big city with many canals," he said. "He may have had an accident.