Before revision: In 1983, extensive boundary changes led to notional general election results being jointly calculated by the BBC and ITN for the previous general election in URL Further notional results were created for the 1997 general election (to compare with the 1992 general election), in 2005 (to take into account the reduction in the number of Scottish constituencies brought about by the establishment of the Scottish Parliament), and in the 2010 general election (to compare with the 2005 general election).
After revision: In 1983, extensive boundary changes led to notional general election results being jointly calculated by the BBC and ITN for the previous general election in URL Further notional results were created for the 1997 general election (to compare with the 1992 general election), in 2005 (to take into account the reduction in the number of Scottish constituencies brought about by the establishment of the Scottish URL and in the 2010 general election (to compare with the 2005 general election).