A staggering 160,000 people are reported missing every year in the UK - equating to one person every 90 seconds.

Of these, over 88,000 are adults and nearly 72,000 are children - although this is likely to be a significant underestimate of actual figures. 

And while missing persons often make it home safe, a minority never do, creating anguish for grieving families as they are left with so many unanswered questions and very little closure. 

According to Missing Persons, 534 people from the UK who have disappeared from across the country and overseas are still missing.

One of the youngest to have vanished without a trace is Sandy Davison, who was just three years old when he disappeared from the garden of his grandparents' house. 

Meanwhile, the UK's oldest missing person, Mary Flanagan, has not be seen since 1959 after vanishing at the age of 16.

Below is a list of just some of those who are still unaccounted for after years of searching across Great Britain and around the world. 

Sandy Davison was just three years old when he went missing while playing in his grandparents garden in Irvine in 1976

Police Scotland released this aged progressed image to give an indication to what Sandy may look like now – almost half a century on from when he went missing

Sandy Davidson – April 23, 1976

Sandy Davison was just three years old when he went missing while playing in his grandparents garden in Irvine in 1976.

The youngster had been outside with his younger sister Donna and the family dog at the property in St Kilda Street on the Bourtreehill housing estate when he was last seen.

According to Donna’s recollection, the gate of the house suddenly swung open and the dog ran out, with Sandy running after him.

Donna quickly went inside to alert her grandparents – but the time they began searching for Sandy he had already vanished from the face of the Earth.

Police were alerted and despite an intensive search by the police and members of the community as well as a high-profile media campaign there was no trace of the toddler.

Donna has worked tirelessly to try and trace Sandy and his whereabouts and led various campaigns to ensure the public are aware of Sandy’s disappearance.

Over the years there have been several theories as to what might have happened to the three-year-old. An initial theory was that he may have followed the dog down to the river and drowned.

Meanwhile, his parents Margaret and Phillip believe that he was abducted by an lonely man seeking a son.

Others accused a man who was delivering leaflets at the time of being his kidnapper.

Police Scotland has continued to work with the family in the hope of identifying any new leads that may help in the search. They previously released an aged progressed to give an indication to what Sandy may look like now – almost half a century on from when he went missing.