It is difficult to argue that Britain had a multi-party system after the 2010 general election.
The Labour, Liberal Democrat and Conservative parties had every seat except one in England.
The SNP had only 6 seats and Plaid Cymru 3 seats and Northern Ireland has an entirely different party system.
Within the Scottish and Welsh party systems, however, the SNP and Plaid Cymru are clearly significant parties and have been in their respective governments and so it is reasonable to argue that these countries have multi party systems.
In the 1950s and 1960s, Labour and the Conservatives only had to be 2 or 3 % ahead of the other party in the general election vote to gain a working majority in Parliament.
Now the Labour or Conservative parties have to be well ahead of the other party to get a majority.
In 1992, the Conservatives were 7% ahead of Labour but still only had a majority of 21.
The changing situation has been disguised by the fact that the Conservatives had big victories over Labour in 1983 and 1987 and Labour had big victories over the Conservatives in 1997 and 2001.
In a situation where the two parties are close in numbers of votes it is more difficult for either to achieve a majority and so the smaller parties may be needed to form a coalition.
In 2010, a coalition between Labour, the Liberal Democrats and the smaller parties was considered. But, in the end it would have been to difficult to manage as a basis to get business through the Commons and some in the Labour leadership felt that the party had lost the election and should not continue. This suggests that Britain is close to a multi-party system with smaller parties being possible partners in government.
Changes since 2010 have accentuated the multi-party nature of British politics.
At it’s height, the UK Independence Party achieved 15-19% in the opinion polls. The Green Party at one point rose above the Liberal Democrats, with 7% in one opinion poll, and, though they may only hold their existing seat, is clearly taking votes from other parties.
With the two main parties close in the opinion polls there was every possibility of another coalition government after the 2015 election with smaller parties included.
But, as the election neared concentration was on which of the two main parties should form the government and which of the two party leaders should be the Prime Minister. This, except for the SNP, squeezed the vote of the smaller parties and Britain may still be a two and a half party system.
Since 2016, the UKIP has collapsed and the Liberal Democrats have greatly reduced. Due to Brexit and the leadership of Jeremy Corbyn in the Labour Party we are seeing divisions and break-away groups in the two largest parties.
The final type of party system that Blondel referred to was the dominant party system.
This is where one party regularly achieves about twice the vote of the next biggest party and so is more or less permanently in government.
The system becomes stuck and there is no alternation in power, as has happened in Japan where the Liberal Democratic Party has been in power almost continuously since 1955, and in Italy. where the Christian Democrat Party was in power from 1948 until 1994, when investigation of widespread corruption led to its disintegration.
There had been discussion as to whether Britain was becoming a dominant party system after the Conservatives gained a majority of 144 in the 1983 general election and had almost twice as many seats as Labour.
They had 42% of the vote to Labour’s 27% ,so someway less than twice as many votes, and the First Past the Vote System accentuated their majority of seats. They retained a large majority in 1987 but the Labour vote recovered to 30%.
Similar discussion took place when Labour won in 1997 and 2001.
In 1997 they had two and a half times as many seats as the Conservatives, though the vote share was 43% to 30%, with First Past the Post again accentuating the majority. A similar result occurred in 2001. Nevertheless Britain can be seen as only temporarily moving towards a dominant party system rather than this being a permanent feature of the system.
The opposition to the Conservative was divided between Labour and the Liberal/SDP Alliance in 1983 and in 1997 and 2001 tactical voting by Labour and Liberal Democrat voters to keep out Conservatives reduced the number of Conservative MPs.
Party systems can be analysed by the ideological positions of the significant parties.
Voters across Europe have no great difficulty, when asked in opinion poll surveys, to rank the parties in their country on a spectrum from left to right.
The Greens have argued that they are neither left nor right in the traditional sense but voters mostly see them as on the left. Regional parties such as the SNP may be more difficult to position but voters see them as centre left.
The Italian political scientist Sartori looked at the competition between parties for votes.
Not all parties compete against each other, for example, given their policies on the environment there are not likely to be many voters switching between UKIP and the Greens.
He argued that systems may be centrifugal so that the main competition is between parties for voters in the centre of the spectrum or centripetal so that parties move to the extremes of the spectrum to gain their voters there.
In systems where there are two main parties, one centre left and one centre right then the system is centripetal with the two parties adjusting their policies to compete for ‘floating voters’ in the centre ground.
The political scientist Otto Kirchheimer called them catch-all parties, losing clear ideological direction and promoting policies with popular appeal.
In Britain, competition between the Conservative and Labour parties can be seen to have had this character with the two parties each claiming that they will be the best at running the economy rather than having sharply different approaches.
They competed for floating voters and for votes from the centrist Liberal party. When Labour moved to the left for the 1983 election their heavy defeat pushed them back to the centre and the same happened, to a lesser degree to the Conservatives after the defeats in 1997, 2001 and 2005 when Cameron looked to change the party’s image.
