An auctioneer has had an "overwhelming" response to an appeal for information about a World War II map believed to have been used by Winston Churchill.
The arrow points to an area just below the number 90 on the map
Experts are now confident the document, which centres on Westerham, near Churchill's home at Chartwell, Kent was used by the wartime prime minister.
It is possible the one inch to one mile Ordnance Survey map may shed light on plans to defend England from invasion.
It is being sold by Shropshire auctioneer Mullock Madeley on 7 June.
Historical documents expert, Richard Westwood-Brookes, said the response was very exciting.
People who knew the area during the war responded from as far afield as Canada and America.
Mr Westwood-Brookes said many of them had seen his appeal on the BBC News website.
A label on the map said: "reputedly used in 1940 at 'Tall Trees' by Winston S Churchill in connection with the defence of SE England against the expected German invasion".
The auctioneer had been unable to trace Tall Trees in any archive but was intrigued that it was so near Churchill's home.
An arrow on the map indicates a point about one mile south-east of Westerham at a place called Charts Edge.
The map centres on Westerham, near Churchill's home at Chartwell
"One person pinpointed a house that was known as Chart Edge and was known in the area for its very tall trees," said Mr Westwood-Brookes.
"It was common practice at the time if you wanted to keep a place top secret that you would give it a nickname.
"The house is still there. I cannot say with 100% certainty that it is the place on the map but everything is coming together incredibly well."
The map is being auctioned at Ludlow Racecourse with an estimated price of £300.
"Who knows what it will go for?" said Mr Westwood-Brookes.
"I am much, much more excited by the historical interest of finding something that nobody else knew about."
He said further investigation might provide historians with new evidence about Churchill's movements during the war.