The UK has had elections using Proportional Representation when we were part of the EEC, later to be the European Union. Due to the results, I not in favour of this.
In 2019, the Brexit party got the highest percentage of votes in the European Elections which meant that Nigel Farage won it, though I will admit with the Lib Dems, centre and left wing parties got over 50% of the vote.. In 2014, Brexit supporting parties won over 50% of the vote (a combination of UKIP, the Conservatives and the DUP equalling 50.5% of the vote, Nigel Farage getting the most votes again this time as part of UKIP. If those elections had been for Head of State, we would have had Nigel Farage in office since 2014, but if for the UK Parliament, that would have meant that he was our Prime Minister since then instead.
In 2009, the Conservatives got the highest vote margin with 27.4% of the vote, UKIP coming second with 16%. Combined with the homophobic DUP (0.6%) and the far right BNP (6.2%), the right wing of UK politics got over 50% of the votes. in 2004, adding up the votes of the Conservatives, UKIP, the Ulster Unionists, the DUP, the BNP and the English Democrats, they come to 48.6% of the vote. The Liberal Democrats got 14.4% of the vote and would have needed to join a much broader coalition to have a chance of getting left wing and centre ground parties over 50%, but with the numbers of parties there, I am not sure that would have been feasible. The possibility of a centre and left wing coalition would have been present in 1999, but that would again depend on the Liberal Democrats, with 11.9% of the vote joining with Labour, and parties, formed due to Labour not being left wing enough also joining it. This is of course assuming that the Liberal Democrats joined such a coalition and did not go it alone or even joining with the Conservatives as they did in 2010.