Original End Of Month Data. Source: London And Cambridge Economic Service, Special Memorandum No. 37, P.7
This NBER data series m11019 appears on the NBER website in Chapter 11 at http://www.nber.org/databases/macrohistory/contents/chapter11.html.
NBER Indicator: m11019
Release: NBER Macrohistory Database
National Bureau of Economic Research, Index of Prices of Fixed Interest Securities for Great Britain [M11019GBM361NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M11019GBM361NNBR, February 13, 2016.