Scam ‘Fake police phone call’?

A lady in the village has received a ‘phone call purporting to be from an officer at Charing Cross Police Station asking if they have a friend, or know of an acquaintance with a certain name.
The lady fearing the call may be a scam put the phone down on the caller before he had finished talking, then, having second thoughts that the call may be genuine rang the Metropolitan Police back asking if the call could possibly be from someone at Charing Cross Police Station only to be told that as the Charing Cross Police Centre was so large they were unable to confirm!
It’s not known of what form the scam may have been had the caller been allowed to finish what he was saying or if it was actually a scam?
Anyone who has received similar calls or may have any other information please contact Hadlow Down Neighbourhood Watch at