The plan was directed, and named after, SS Major Bernhard Kruger, who set up a team of 142 counterfeiters from among inmates at the Sachsenhausen concentration camp. Beginning in 1942, the work of engraving the complex printing plates and breaking the code to generate valid serial numbers was extremely difficult, but by the time Sachsenhausen was evacuated in April 1945 the printing press there had produced 8,965,080 banknotes with a total value of £134,610,810. The notes are considered the most perfect counterfeits ever produced, being extremely difficult to distinguish from the real thing.
Following the evacuation of Sachsenhausen, the counterfeiting team was transferred to Ebensee in Austria, a sub-camp of the Mauthausen concentration camp, from where they were liberated by US forces on 5 May 1945. It is believed that most of the notes produced ended up at the bottom of the lake at Ebensee, but examples continued to turn up in circulation in Britain for many years, which caused the Bank of England to withdraw all notes larger then £5 from circulation, and not reintroduce the denominations until the early 1960s (£10), 1970 (£20), or 1980 (£50).
The counterfeiting team also turned its attention to US currency, producing its first 200 $100 bills on 22 February 1945 with full production scheduled to start the next day, but the Reich Security Main Office ordered the work halted and the press dismantled.