Use the link below to view the full research report that looks at reductions in inherited SERPS, legislated for in 1986, originally intended to be introduced from April 2000, but delayed following a campaign around inadequate publicity.
A separate note: CPB-07631 “Inheriting additional State Pension” provides more general overview of the provisions both in the old system (for those reaching State Pension age before 6 April 2016) and the new one (for those reaching State Pension age after that date).