A watermark appeared across the middle of every note; it differed depending on the value of the currency and the alphanumeric serial designation used.[8] According to John Keyworth, the curator of the Bank of England Museum, as the paper currency had never been successfully counterfeited, the Bank of England "was a little complacent about the design of its notes and the production of them";[9] he described the notes as "technologically ... very simple".[10]