Frank Archer has been missing since Saturday afternoon.
Detectives have appealed for help in finding a missing Pinner pensioner who suffers from dementia.
Frank Archer, 79, who suffers from the disorder and other health problems, was last seen at his home in The Avenue on Saturday.
Police believe he has a Freedom travel pass and is known to travel on buses, as well as having a keen interest in trains and railway stations and being a regular customer at betting shops.
Mr Archer has links to Harrow, Brent, Camden and Islington but police think he could be anywhere in the capital.
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