Revealed: Missing William Tyrrell was in foster care at time of disappearance

It has been revealed that missing three-year-old William Tyrrell was in foster care at the time he vanished nearly three years ago.

He was last seen wearing a Spider-Man costume playing outside his foster grandmother's home in Kendall on the NSW mid-coast in 2014.

Despite efforts from the NSW Government to keep his status as a foster child secret, the New South Wales Supreme Court of Appeal ruled that the information is in the legitimate public interest.

William was last seen wearing this spider-man costume. Source: NSW Police

Facebook vigilantes group Walking Warriors for Missing Children wanted the information released because they say they are fighting for a coronial inquest.

The government fought in the Supreme Court against the suppression being lifted and having the information released to the public.

They said that the information would have a stigmatising effect on William Tyrrell.

William was a foster child at the time of his disappearance. Source: AAP

However, on Wednesday, the Court of Appeal ruled that the adverse affect on his welfare was diminished by the tragic probability that he is dead.

The disappearance of William has become one of Australia's most baffling and puzzling missing person's case to date.

About 10.30am on September 12, 2014 William, then aged three, was playing in the yard of his grandmother’s home on Benaroon Drive, Kendall, when he disappeared.

Within a few short hours, hundreds of local residents and emergency service workers combined to search the rural township, looking in forests, creeks and paddocks for the boy.

William disappeared from this house in NSW mid-north coast town of Kendall. Photo: 7 News

The speed and coordination of that local search allowed police to form the view very quickly that William had been kidnapped.

His case made national headlines.

He would have celebrated his sixth birthday in June.

There is no suggestion William's biological or foster family had anything to do with his disappearance.

His parents have been ruled out as suspects.

Police are still trying to piece together what happened to William. Source: AAP