@Subotai:
When was the time that changed power structures in UK so that the British P.M had more power than kings or queens? 1700? 1750? 1800? 1850?
Because the reduction in royal powers in Britain took place over many centuries, and because Great Britain has an uncodified constitution, it’s hard to point to one specific date. For example, the Magna Carta of 1215 was an early step in the process of placing limits on royal authority. The English Civil War was largely a power struggle between Parliament and King Charles I (who, in a fairly dramatic application of the principle that the authority of the sovereign should be curbed, ended up on the wrong end of an executioner’s axe in 1649). The Glorious Revolution of 1688 and the subsequent Bill of Rights 1689 also contributed greatly to the establishment of parliamentary supremacy in Britain.