Page "Zinoviev letter" Paragraph 15

This book motivated the British Foreign Office to initiate a study of their own.

For three years Millicent Bagot of MI5 delved into the archives and conducted interviews with surviving witnesses.

She produced a long account of the affair, but the paper ultimately proved unpublishable because of its containing sensitive operational and personnel information.

Still, Bagot's work would prove important as a secondary source when the Foreign Office revisited the matter nearly three decades later.