No. 5 Group R.A.F. Operation Order No.B976 Most Secret original file copy, unsigned, dated 16th May 1943 Ref.5G/101/54/Air issued by H.V. Slattery G/C Senior Air Staff Officer No. 5 Group Royal Air Force under headings INFORMATION, INTENTION, EXECUTION, INTERCOMMUNICATION, DISTRIBUTION, being the order setting in process the Dambuster Raid by 617 Sqn. May 1943, stencil printed on six foolscap sheets