The referendum vote will change British politics whatever the outcome. Putting to one side the longer-term ramifications of a potential Brexit and what it would mean for unpicking the relationship between the UK and the EU, neither Cameron or Corbyn will be sitting comfortably after the 23rd June.
So what are some of the potential outcomes that we should be prepared for?
A snap election - the Fixed Term Parliament Act contains provision for calling an early general election and there has been speculation that it would be needed in the event of a Brexit vote. With Cameron's credibility torn to shreds he would not have the authority to negotiate with the EU it is suggested. Actually, a snap election could also suit those in the Labour Party looking for an excuse to challenge Corbyn as well so amongst many Parliamentarians the idea could find favour. Whether any of the parties could afford another election campaign is more doubtful. There is also the self-preservation of politicians to consider. Would the Conservatives be able to secure another majority?
The Cameron challenge - there will be one, it is only a matter of when it will happen. In the event of Brexit, he will barely have time to pack his bags but even if the country votes to remain, Cameron appears to have unleashed a Conservative armageddon. Whilst his initial decision to hold a referendum may have helped save seats from UKIP in 2015, the EU fissure has re-opened in his own party now the campaign is underway. There is no way that Cameron himself can heal the wounds so a new leader will be needed. By pre-announcing his intention to step down, Cameron has also opened up the space for challengers to position themselves. It is not as though the PM has a bedrock of party support that he can rely on either. From gay marriage through to derogatory comments about MPs ignoring the views of their constituencies, Cameron has eroded what support he did have back in 2005.
A long-winded challenge - there could be a whole range of candidates that put themselves forward to replace Cameron. The more there are, the longer the process is likely to take. The longer it takes, the more likely it is to turn nasty. There will doubtless be several candidates from both the Remain and Brexit camps, a unity candidate or two and a few looking to boost their credibility to try to get a decent Cabinet position.
The Corbyn backlash - very few people are claiming that Corbyn is having a good campaign. Sadiq Khan has, for instance, made a pretty robust appeal for Corbyn to pull his socks up and get the Labour vote out to get a Remain result. Accusations of a lack of commitment and a secret anti-European agenda continue to dog Corbyn despite have made several good speeches. If the vote is close and particularly if Brexit happens then his lack of engagement will be used against him. A poor result for Labour in a snap election would bring Corbyn's time as leader to an end and would mean that MPs would not have to make a challenge themselves. If not, there is one last window of opportunity around July to deliver a principled challenge before the party's policies and processes change at the conference in September.
Neverendum - just as the SNP will not rule out another vote in Scotland, the Conservative Party may find itself forced to maintain a commitment to another future referendum. In the event of a leading light from the Brexit camp replacing Cameron, the attraction would be obvious but even a pro-European leader would know that their party, the local associations, will need to have bridges rebuilt and will remain generally Eurosceptic.
The future of the UK - Remain are already talking widely about the possibility of a pro-EU Scotland holding another independence referendum in the event of Brexit and similarly a derailing of peace in Northern Ireland. Regardless of whether either of these happen, the result will cause further divisions between Westminster politics and the rest of the UK.
Referendums - politicians from all parties have shown that referendums are part of modern British politics. New Labour had devolution, the Coalition had electoral reform and Scottish independence, and now the Conservatives have Europe. Decisions being put directly to the people are now part of the political lexicon and there is no reason not to expect more of them in future. There will certainly be demands for them.
The result of the EU referendum will resolve very little, let alone the eventual nature of the relationship between the UK and the EU or between the UK and individual Member States. It is only the start of a major shift in UK politics.