Richard Szypulski (letters, 13 May) may well be right to chide the Sage for his assumption that the days of two-party politics is over, and that has largely to do with our first-past-the-post electoral system (FPTP).

As soon as any one party has a majority in parliament, whether Labour or Tory, it is clearly not in their interest to introduce a proportional system under which they would lose. Expect no change for at least five years.

Proportional Representation will not be on the parliamentary agenda before 2020 as it wasn't under Labour between 1997 and 2010.

While our FPTP system is clearly thoroughly undemocratic, not everything in the proportional representation garden smells sweet. We need to be cautious: Under the PR system operating in Norway and Germany (among others) is the so-called Five% Threshold. Parties which obtain less than 5 percent of the popular vote are eliminated from the contest.

Were that same system to operate here, all of the Scottish National Party (with 4.7%), the Greens (with 3.8%) and Plaid Cymru would not be represented in parliament.

We would have MPs from the Conservative, Labour and LibDem parties and UKIP which had the following proportions of the popular vote respectively: 36.9, 30.4, 7.9 and 12.6.

With the SNP all but sweeping the board in Scotland, a PR system similar to the German one would only be viable if the UK were to become a Federal Monarchy (in the same way as Germany is a Federal Republic) in which each part of the federation elected a given number of MPs to both its own senate and to Westminster.

Another factor is that under PR, coalitions would almost always become inevitable. This is a double-edged sword. This may be an advantage, as in 2010-2015, when it was perceived that the Lib Dems exercised a moderating influence over what the press described as “Conservative excesses”.

On the other hand, the need for coalition partners could result in very minor parties exercising excessive influence.

Dr Michael Johnson

Kevin Gardens

Brighton