Right. Have cobbled something together. Based on:
Northern Ireland - Irish parties votes only, uplifted so they are 100%
Wales - assumed all PC votes cast here, uplifted, remainder shared between 'Big 3'
Scotland - assumed all SNP votes cast here, uplifted, remainder shared between 'Big 3'
England - assumed no national votes here, smaller parties vote checked on uplift, all under 5%, so Big 3 uplifted to be 100%
(Yes, I know this is highly unscientific, but it's to give a vague idea....)
The biggest party in each election is the same as the winner under FPTP (Tory 1979-1992, Labour 1997-2005). BUT - this is never enough to govern alone.
If the nationalists could have been bribed sufficiently, they were a big enough block in 1997, but I have assumed this wouldn't happen.
By these calculations, the liberals / alliance / LDs would have been a coalition partner in every election since 1979...
