Steve Roberts, a police officer in the town of Doncaster, said the handwritten letter appeared to have been written by Churchill's wife, Clementine, and is addressed to a South Yorkshire woman, The Independent said Saturday.

"The address on the letter is not in Doncaster but it is South Yorkshire. I am confident it is not a reproduction as it is handwritten on both sides," Roberts said.

The letter is dated 1942 and thanks its intended recipient for a donation to a Red Cross effort that Churchill's wife headed, The Independent said.

The newspaper said the letter was found last month when police raided a home in the town of Mexborough, but its owner has yet to be located. An unspecified amount of heroin was also allegedly found in the home, police say.