The discussion over the televised leaders’ debates rumbles on as Prime Minister David Cameron calls for the inclusion of the Democratic Unionist Party (DUP). Earlier this month the broadcasters seemed to have found two workable formats with Sky hosting a head-to-head debate between the Conservative Prime Minister David Cameron and Labour’s Leader of Opposition Ed Miliband, and the BBC and ITV staging a seven party debate, where Liberal Democrats leader Nick Clegg, UKIP leader Nigel Farage, the Greens leader Natalie Bennett, the SNP leader Nicola Sturgeon and Plaid Cymru leader Leanne Woods join Cameron and Miliband for another showdown.

Leaders but not MPs

While these debates serve as a build-up for the general election in May, four of the aforementioned leaders are not Members of Parliament (MPs). Natalie Bennett holds no elected office; Nigel Farage is only a Member of the European Parliament; whereas Nicola Sturgeon and Leanne Woods are members of the devolved Scottish Parliament and Welsh Assembly respectively.

At the same time, these four parties have their own MPs at Westminster. The sole MP of the Greens is Caroline Lucas, who was also their leader until 2012. For UKIP, they gained two MPs through by-election victories of Conservative defectors Douglas Carswell and Mark Reckless last year. While the SNP’s focus remains at Holyrood, their number of MPs are likely to dramatically increase from the current total of six in the upcoming election, according to poll figures. Welsh-based Plaid Cymru also have three MPs. The four parties have chosen party leaders from outside of parliament instead of their parliamentary representations.

What has changed?

For a political system long centred on Westminster and its two and a half major parties, it is a very striking change to have the media focusing so strongly on so many politicians outside of Parliament. There are three main reasons to explain this.

The first, and most talked about, is the slow but steady decline of support for the two major parties. Labour and the Conservatives have gone from winning over 95% of the vote in the 1951 general election to just 65% in 2010. However Britain’s restrictive electoral system squeezes out smaller parties that are not regionally concentrated. Well before UKIP’s surge in the opinion polls and their stunning successes in the latest local and European elections, they already secured over 3% of the popular vote in 2010. Under a proportional system this would have afforded them around 20 seats at Westminster, and Nigel Farage would very likely have entered Parliament (at the last election he challenged Speaker John Bercow in Buckinghamshire). Instead they did not win a single seat, meaning that UKIP’s decision to have a leader outside of parliament was made for them. Hitherto, minor parties in this country had struggled to gain recognition as serious parliamentary actors in their own right, whereas their counterparts on the continent such as the German Free Democrats have long been seen as potential coalition partners. For this election though, smaller parties are no longer an irrelevance and cannot be ignored by the media as shown by the huge online petition for Natalie Bennet’s inclusion in the leader debates. However they, and their leaders, remain largely outside of the parliamentary system.

Nevertheless this is not enough to explain the surging phenomenon of non-parliamentary leaders. Previous constitutional reforms mean that Westminster is no longer the only centre of British political life. Politicians can gain publicity and respectability outside of Westminster, and regional parties can focus on their representation in devolved legislatures.

The SNP and Plaid Cymru are prime examples to illustrate this. Without any hope of coming close to a majority at Westminster, the SNP’s influence outside of a hung parliament is always going to be limited. By contrast it has a real chance of exerting parliamentary influence in the Scottish Parliament (founded in 1999) with the help of a more proportional electoral system. Having formed a minority government in the Scottish Parliament in 2007 and then winning an overall majority in 2011, the SNP was further able to directly negotiate with the Coalition government in Westminster, and secure an independence referendum through the mutually accepted “Edinburgh Agreement” in 2012. That is clearly something the small number of MPs in Westminster can never dream of achieving. Thus given the SNP’s primacy for the Scottish Parliament rather than that for Westminster, it makes sense for the party leader to be based in Holyrood. Furthermore, having a leader detached from London is consistent with the SNP’s strategyof blaming the unionist parties and Westminster for not always having Scotland’s best interest in mind. Though a much smaller party Plaid Cymru have won moderate support in Welsh Assembly elections and were junior partners in the coalition government from 2007 to 2011. The SNP and Plaid Cymru can now present themselves as serious parties of government whilst also maintaining a distance from the tainted Westminster bubble.

UKIP and the Greens have benefited from European Parliament elections in slightly different ways. Members of the European Parliament (MEPs) have been elected through a regional proportional representation system since 1999. The change in electoral system and the propensity of voters to use European elections as a chance to protest has resulted in UKIP’s gradual increase in their number of MEPs. Last year UKIP became Britain’s largest party in the European Parliament, marking it the first time where a party other than the Conservatives or Labour has won the largest number of seats in a national election since the Liberals at the December 1910 general election. Similarly, the Greens have also been consistently making progress in European Parliament elections. Though the powers and privileges of being an MEP is far from that of a Westminster MP, it does give both UKIP and the Greens a chance to establish themselves as a party capable of representing the electorate. In particular, UKIP has attracted significant media coverage through their remarkable electoral performances in recent European Parliament elections, and has capitalised on the exposure to posit themselves as a viable alternative party for government. The phenomenal success in last year’s European Parliament elections has boosted the national status of Nigel Farage and of UKIP, greatly improving their prospects at the 2015 elections.

A final factor that has facilitated the rise of prominent party leaders outside of Parliament is the strong anti-political establishment sentiment that has been simmering in recent years. With austerity policies which disproportionately burden the lower socio-economic class being imposed, parties recanting and failing to deliver on electoral promises, and MPs across all Westminster parties being extensively involved in the parliamentary expenses scandal, the electorate have begun to view Westminster as generally out of touch, untrustworthy and corrupt. Being outside of Westminster is no longer such a disadvantage. Leaders outside of parliament can distance themselves from the unpopular political elite, and remain untainted by scandals and policy failures of government. Not having held the levers of power is in fact a blessing in disguise. Knowing this too well, Nigel Farage has declined to run in by-elections in recent years, despite a streak of strong performances by relatively unknown UKIP candidates. Had he run he would have had a realistic prospect of winning but he calculated that popularity and political capital would be greater if he stays away from Westminster.

So what?

The lack of parliamentary status of leaders of the Greens, UKIP, the SNP and Plaid Cymru shows that the British party system has adapted to a dealignment of the public with the two major parties. Smaller parties can still achieve parliamentary representation, influence and popular attention despite not being significantly represented in the Westminster parliament. Minor parties seem to have found a way to make their own mark, even in an electoral system that cannot keep up with its voters.

However there are dangers to all this. Bennett, Farage, Sturgeon and Woods – if they all make it to the televised debates – will be able to attack leaders who have been in Parliament, while they themselves would not have to defend their own records in parliament.

What happens after the election?

If the status of political outsider pays off, where smaller parties are able to break into Parliament in substantial numbers, they will then have to face up to the challenges of being in Westminster. In the event of a hung Parliament, the Greens and UKIP will have to face tough legislative decisions regardless of whether they decide to form a coalition with other parties. Would UKIP MPs back EU policies that tighten immigration rules but have no plans for Britain’s withdrawal from the EU? Would Green MPs back a modest rise in the minimum wage that falls short of the living wage? If the SNP hold the balance of power, will they form a coalition government with Labour, or stay in opposition, and potentially allow their arch-enemy, the Conservatives, to remain in office?