A toddler missing for ten hours was found early today dangling over a stream - cold, wet and trapped in the roots of a tree.

Police say it's "remarkable" that little Merlin Reid was unharmed after taking a mile-long walk through a slurry pit and bogs and over a railway line.

Merlin disappeared from his grandparents' house near Billingshurst at 2pm yesterday. He was found by a local farmer around midnight.

Superintendent Mark Streater, who led the search operation, said Merlin was safe and well but cold and wet. He was reunited with his family and taken to Crawley Hospital.

Mr Streater said: "It is so unusual for a boy of this age to have found his way half a mile across fields, to have been lost for ten hours and to be OK.

"Given the nature of the area, with a long driveway, we didn't believe he had been abducted. We believed he had been lost but we of course had to keep an open mind."

During his disappearance, Merlin had managed to walk through a "minefield" of dangers including a railway line, a slurry pit, bogs, a disused sewage works and finally the 3ft deep stream.

Merlin was finally found by local farmer Jason Fisher, who had joined the search.

Mr Fisher said: "I saw the jacket and just followed a path down to the stream. As I walked along the stream I thought to myself, 'Please don't let me find a body'.

"I carried on walking and spotted this tiny little head. He was standing upright with his little legs wedged between two tree roots, dangling over the stream.

"He had a look of complete shock on his face. The little thing never made a sound. His eyes were as wide as dinner plates."

The search operation involved 50 officers, including dog teams and the force helicopter, plus firefighters and local volunteers. The Army had been due to join the operation at first light.

Mr Streater called Mr Fisher a hero, adding: "It is a remarkable tale. For a two-and-a-half-year-old boy to go missing for ten hours on a cold, wet February night, and to walk through a minefield of dangers including bogs, a railway line, slurry and water is truly amazing.

"He has walked over 2km from his grandparents home and has somehow, by the grace of God, become entangled in the roots of that tree.

"If he had fallen into the river, he would clearly have drowned and even if he had been missing for another two hours, he could have succumbed to the cold."

Merlin's grandmother, Alexandra Reid, said today: "He's a darling little boy. We love him dearly. It was such a shock.

"How he managed to get so far in his little wellies I'll never know. We are just so relieved."

Mrs Reid, 64, and her husband Richard, 68, were looking after Merlin and his five-year-old brother because their parents, Andrew and Hui Ling, had chickenpox.

Mrs Reid said: "Last night was too horrible to contemplate but the people and the police were incredible. They were so kind.

"All sorts of people were looking and were jumping for joy when he was found."

Assistant Chief Constable Geoff Williams, who joined the search, said: "Naturally we are delighted that Merlin was found safe and generally in good health.

"This was a significant policing operation for Sussex Police involving a number of agencies and personnel. There were many heroes on the night, ranging from police officers who came in from holiday to help, to volunteer agencies and the community themselves.

"It is truly heartwarming that so many people can be moved to help. We all had one aim, which was to find Merlin."

Merlin went missing from the area of Bullbrook House Farm in Valewood Lane, Barns Green, at about 2pm yesterday.

Police had asked members of the public to search outbuildings for Merlin, described as being of Chinese appearance, who was wearing a blue rainproof top, blue trousers, white wellington boots with sheep on and a blue tweedy jumper.

The specialist search and rescue team looking for Merlin was set up by PC Gary Relf, who made headlines last weekend when he rescued a mother and child trapped in the sea.