equipped the V bomber fleet and the English Electric Canberra. In the V-force, Mk. IXA was tied into both the bombsight and navigation system to provide a complete long-range Navigation and Bombing System (NBS). In this form, H2S was last used operationally during the Falklands War in 1982 on the Avro Vulcan. Some H2S Mk. IX units remained in service on the Handley Page Victor aircraft until 1993, providing fifty years of service. Etymology of "H2S" The radar was originally called "BN" (Blind Navigation), but it quickly became "H2S". The genesis of this remains somewhat contentious, with different sources claiming it meant "Height to Slope"; or "Home Sweet Home". The "S" was already being used by the airborne interception radar team as a deliberately confusing acronym for its operating wavelength in the " " range, which ultimately gave name to the S band. It is widely reported that it was named after hydrogen sulphide (chemical formula H2S, in connection with its rotten smell), because the inventor realized that had he simply pointed the radar downward instead of towards the sky, he would have a new use for radar, ground tracking instead of for identifying air targets and that it was simply "rotten" that he had not thought of it sooner. The "rotten" connection, with a twist, is propounded by R. V. Jones, director of the Air Ministry's scientific intelligence unit. He relates the tale that, due to a misunderstanding between the original developers and Lord Cherwell, science advisor to Winston Churchill, development of the technology was delayed as the engineers thought that Lord Cherwell did not like the idea. Later, when Cherwell asked how the project was progressing, he was most upset to hear that it had been put on hold, and repeatedly declared about the delay that "it stinks". The engineers called the resumed project "H2S" and later, when Cherwell inquired as to what H2S stood for, no one dared tell Cherwell that it was named after his phrase. Instead, they pretended, on the spot, that it meant "Home Sweet Home", which was the meaning that Cherwell related to others (including Jones). Development Genesis After the Battle of Britain, RAF Bomber Command began night attacks against German cities. Although Bomber Command had reported good results from the raids, the Butt Report showed only one bomb in twenty landed within of the target, half the bombs fell on open country,