OK, so if we take the condition in the UK around the late 1970s just pre-Margaret Thatcher, lets assume that Michael Foot lost the leadership competition to Tony Benn. Labour won the 1979 election (causing Margaret Thatcher tor esign as Conservative leader) and adopted an extreme-left wing manifesto (as in 1983). At that time I can remember a Trades Union leader (may have been Scargill, I can't remember now) saying that Britain didn't need elections since the Trades Unions represented a majority of people in the UK so they should select the government.
So, Labour lost in 1983 but the Unions started a general strike. Without Margaret Thatcher, the willingness to fight is gone and the government collapses. A Labour Party that's effectively a Trades Union poodle takes over. When the next election is due, the Trades Unions are as good as their word, the elections are cancelled and they "select" the Labour Party as the next government. They declare a people's republic with the General Secretary of the TUC as President.
The result is the country splits essentially along geographical lines, with the South East, North Wales, East Anglia, Highlands and some of Noprtehrn England declaring for the Queen as the Loyalists while the Midlands and Industrial North declare for the People's Republic as the Unionists. Civil war erupts and goes on for almost 15 years without either side gaining a clear advantage. Eventually, Prince Charles who reveals completely unexpected talents as a military commander routes the unionist forces and eventually defeats them is a great battle at Naseby. Parliament and democracy are restored.
QED.