According to research, around three in every five people with dementia will go missing at least once during the course of their illness.
It can be a very frightening experience for them but also their family.
Now a new scheme, the first of it's kind in the world, is being piloted in the Thames Valley to help find people with memory problems who go missing.
Mel Bloor talks to dementia patient Ralph Burridge and his wife Jan, George Holland - the great nephew of missing Sussex pensioner Nellie Herriott, Dr Rupert McShane from Oxford Health NHS Foundation Trust who came up with the idea, volunteer Naomi Manuel and Service Manager Deborah Ginns.
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Fog is affecting Southern England this morning causing delays to flights, ferries and the road network.
Tuesday's weather for the east of the region
Tuesday's weather for the west of the region