Big unanswered questions as new search for Madeleine McCann under way

Dense shrubs, empty barns, disused wells and dirt tracks - the police here have got their work cut out if they're to find evidence relating to Madeleine McCann's disappearance.

At 6am, before police cordons were put up, we spoke with an officer - a balaclava covering his face - manning one of the forensic tents. "It's a large area," he told me.

"A different place will be searched each day." Gusty winds blow up dust on the dirt tracks. The land is used by dog walkers and hikers, and is sparsely populated.

But as the crow flies, it's only a mile or so from where the three-year-old was last seen while on holiday with her family in Praia da Luz in 2007. As we stood by the police van, out for his morning run was Tony Gallagher, a Brit who has lived within this new search area for 20 years.

He remembers when it all happened. "I know for a fact that they searched up here 20 years ago," he said.

"I'm not sure what they're hoping to find, because even locals were searching." It's one of the big unanswered questions: Just what intelligence is this latest search based on? Has someone come forward? "It feels strange, you know," Tony adds. "I think it will be for the people in Praia da Luz...

because it had a whole negative impact there 20 years ago in terms of business and tourists coming and everything. "And I hope for the locals that doesn't happen again." At 9am, two vans and three cars arrived, all with German number plates.

Inside, police - some in camouflage uniforms - were ready to begin the search. Police in Germany had asked officials in Portugal for access back in April, so this has been in the planning for weeks.

Madeleine's disappearance is one of the most high-profile missing-person investigations in the world. It's why every new search brings the world's media.

At one point, more than 20 journalists were broadcasting live alongside us, lining the road opposite the police. While this new search brings fresh hope, journalists and, more importantly, Kate and Gerry McCann have been here before, many times.

Around two years ago, a dam about 45 minutes from here was searched, but nothing was found. Read more:New search for Maddie could be 'last throw of dice'What we know about new searchesMcCanns remember daughter on anniversary of disappearance In May, on the anniversary of these tragic events, her parents said they will leave "no stone unturned" in the search for their daughter.

Eighteen years on, it is a poignant moment - Madeleine would have turned 22 last month..