Dorothy O ' Grady Dorothy Pamela O ' Grady ( 25 October 1897 Clapham , London - 1985 Lake , Isle of Wight ) was the first British woman to be found guilty of treachery in World War II . She was sentenced to death but on appeal the sentence was commuted to 14 years ’ penal servitude . Biography . She was adopted soon after birth by a British Museum official , George Squire . Her mother died when she was 11 and her father then married his housekeeper who treated her in a vindictive manner . By the age of 13 , she was living in a home where young girls were trained for domestic service . In 1918 , she was convicted of forging bank - notes and in 1920 , while in service in Brighton , she was found guilty of stealing clothing and was sentenced to two years ’ penal servitude . On her release , she moved back to London where she worked as a prostitute until 1926 when she married a London fireman 19 years older than her , Vincent O ' Grady . On his retirement , they moved to Sandown on the Isle of Wight where she ran a boarding house , Osborne Villa . On the outbreak of war in 1939 he was recalled to the London Fire Brigade for wartime service leaving O ’ Grady behind . Wartime activities . The Isle of Wight is immediately opposite France across the English Channel and commands the Solent which is the sea approach to the major ports of Southampton and Britain ’ s biggest naval base , Portsmouth . Its strategically important coastline was subject to strict restrictions on movement throughout World War II . With her husband away on war service , O ’ Grady was seen frequenting restricted coastal areas while walking her dog , sometimes at night . Her activities were monitored and her mail intercepted and she was found to be making drawings and detailed maps of the coast . She was then caught in the act of cutting some telegraph wires and arrested . Trials . In August 1940 , O ’ Grady was charged with being in a prohibited area and granted bail . But when she failed to attend the court hearing at Ryde Magistrate ’ s Court her home was searched and she was eventually apprehended living under the assumed name of Pamela Arland in a boarding house at Totland Bay on the west coast of the island . In December 1940 , the case against her was heard " in camera " at the Hampshire Assizes , Winchester . As there was no indication as to just how the information gathered by O ’ Grady was to have been communicated to the Germans she was tried not as a spy or agent , but as a saboteur . She was found guilty of two offences under the Treachery Act ; of making a plan likely to assist the enemy and that with intent to help the enemy she cut a military telephone wire . She was also found guilty of two offences under the Official Secrets Act ; that she had approached a prohibited place and that she had made a plan that might be useful to the enemy . On 17 December 1940 , she was sentenced to death . Her subsequent appeal was heard in the Court of Appeal in London in February 1940 and on 10 February 1940 the sentence was commuted to fourteen years ’ penal servitude . Prison and release . On conviction , O ’ Grady was moved from Holloway Prison to serve her sentence at Aylesbury Prison , Buckinghamshire . There she was examined by the prison psychologist who found she had an IQ of 140 , but that she was also mentally disturbed exhibiting a range of masochistic behaviours . O ’ Grady served 9 years of her sentence and was released in early 1950 . She then sought to give her account of events and in an interview with Sidney Rodin , a reporter for the " Sunday Express " , she asserted that the whole episode " was a huge joke " and that " being sentenced to death gave her the biggest thrill in her life " . Subsequent life . O ’ Grady returned to her home at Sandown where she resumed her life as a boarding house keeper . Her husband died in 1953 and in 1969 she went to live in a residential home at Lake on the Isle of Wight where she remained until her death in 1985 . Declassified files . The papers for the wartime prosecution were released by the National Archives in 1995 under reference HO 45 / 25408 . These disclosed that the maps O ’ Grady had drawn of the Isle of Wight ’ s coastal defences were accurate and would have been of great assistance to any German attack on the island . Unknown at the time , as part of Operation Sea Lion , the Germans intended to invade the island with an assault by the Wehrmacht ’ s 9 . Armee under Generaloberst Adolf Strauss . In 2010 it transpired that the National Archives file was no longer available , " misplaced when on loan to government department " .