Modernise UK elections with mandatory preferential, weekend voting

We propose a system of preferential voting in which people could rank candidates without "wasting" votes on tactical choices. We think mandatory voting (like Australia's ≈90% turnout) means politicians must appeal to everyone, not just those who show up. You could still spoil your ballot. In addition to this, we think weekend elections would stop forcing people to choose between democracy and work. We think it is time to modernise what we feel is a Victorian-era system.