Carl Court / Getty Images Jeremy Corbyn's terrible week with his parliamentary party continues. Despite a thousands-strong rally of supporters on Monday night, the Labour leader lost a confidence motion on Tuesday when around 80% of MPs voted against him in a secret ballot. But what happens now? The vote does not remove Jeremy Corbyn as Labour leader. Jeff J Mitchell / Getty Images Tuesday's secret ballot was entirely symbolic: There is nothing in Labour party or parliamentary rules requiring a Labour leader to step down after a no-confidence motion.It is true that more conventional politicians would probably resign at this stage, as attempting to run a parliamentary party without the support of your MPs is a near-impossible task. Corbyn has yet to fill all the vacancies made by the waves of resignations since Sunday, and following the vote will now struggle to compel MPs to support his policies in parliament.However, the Labour leader, his team, and his political allies have repeatedly said he will not resign and will only step aside if forced to by a vote of Labour members – who elected him leader by a landslide in September 2015.Westminster rumours suggest more senior MPs will resign after the vote, including the Whips Office and, possibly, the party's deputy leader, Tom Watson.If Corbyn was to change his mind and yield to the pressure – which is seen as unlikely – Watson would, under party rules, serve as acting leader until a new leader was elected.However, in a statement following the declaration of the result, Corbyn said the ballot had "no constitutional legitimacy" and called for "party members, trade unionists and MPs" to rally behind his leadership. Why doesn't Corbyn call his MPs' bluff and announce a leadership election? Matt Cardy / Getty Images The Labour party rules on leadership elections are very detailed in some places, and unspecific in others.One thing that is very clear is that if there is a "vacancy" for leader, candidates must be nominated by at least 15% of Labour's MPs and MEPs (members of the European parliament) before they are on the ballot. Labour has 229 MPs and 20 MEPs, so anyone wanting to be leader would need at least 38 nominations.If Corbyn wanted to trigger an election himself, he would need to resign, which would create a "vacancy". This would mean he would definitely need at least 38 nominations to appear on the ballot.Corbyn is so unpopular with the parliamentary party that it's not at all clear he would reach this threshold, denying his supporters in the wider party any chance to vote for him. He only succeeded in getting on the ballot in 2015 because some of his colleagues "loaned" their nominations to him, thinking he had no hope of winning. That's not a mistake they'll make twice. So what can Corbyn's MPs do to force him out? Richard Gardner/REX/Shutterstock The only formal way for MPs to oust a sitting leader under the party's rules is to trigger a new leadership election.This can only be done by having MPs and MEPs all nominate an alternative candidate for leader. This needs a higher threshold than when there's a vacancy – it'd take a minimum of 50 MPs and MEPs nominating the same candidate to trigger a contest.Veteran Labour backbench MP Margaret Hodge is at the fore of the movement to arrange this contest, and is seen as a likely "stalking horse" candidate. "Stalking horse" is a term for an ostensible rival for the leadership who would actually stand very little chance of running. The "stalking horse" is easy for MPs to temporarily back, then withdraws from the race once the "real" candidates have emerged. The alternative option is for MPs to unify behind one candidate and select just one challenger from the get-go. Deputy leader Tom Watson and former first secretary of state Angela Eagle, who resigned yesterday, are seen as the favourites to challenge Corbyn.If Corbyn doesn’t resign following the no-confidence vote, this is the course of action his MPs will take. This is where Labour’s ambiguous rules on leadership contests get tricky, though – there is disagreement over whether or not Corbyn would automatically get on to the ballot. What do the rules say about whether a standing leader automatically gets on the ballot? Rob Stothard / Getty Images No one's sure. Or rather, no one agrees.The rules governing launching a leadership contest are one paragraph long and say "nominations may be sought by potential challengers".Jeremy Corbyn's team are very confident that this phrasing means Corbyn himself wouldn't need to gather nominations and would appear on the ballot automatically. They gathered a legal opinion to this effect from senior lawyers at Doughty Street Chambers, according to reports.However, the Labour party has received conflicting legal advice from GRM Chambers, its usual law firm, which says a serving leader would not automatically appear on the ballot.The dispute is tackled in a much greater degree of detail by the Labour-supporting lawyer Jolyon Maugham QC here.The task of settling the dispute is likely to fall to Labour's national executive committee, which oversees the party's rules. Party-watchers are unsure which side the committee would fall on, but Corbyn would certainly have a chance of getting his interpretation through. Theoretically, either side could try to take the matter to the courts, but it's unlikely they would wish to intervene with internal party matters. If Corbyn gets his name on the ballot, will he win? Justin Tallis / AFP / Getty Images Jeremy Corbyn certainly still has strong support among some Labour members and supporters, as his ability to muster a short-notice rally of thousands outside parliament on Monday testified.He won the 2015 leadership contest – which ended only nine months ago – by a landslide. With four contestants on the ballot, he collected just under 60% of the vote in the first round, and led among existing party members, "registered supporters" (people who paid £3 to vote in the election), and trade unionists.As such, Corbyn would seem to be a strong favourite if his name is on the ballot.The big question is whether his support remains as solid as it was, especially now several of his most enthusiastic early backers have subsequently withdrawn their support. Further, a campaign in the wake of the EU referendum, in which the Labour leader was seen to have run a Remain campaign which was lacklustre at best, may provide a rival candidate with good lines of attack, as well as perhaps fuelling new £3 registered supporters using the Labour leadership contest as a means of fighting Brexit.Jeremy Corbyn's team is certainly very confident he could win a ballot of members. With no polling evidence – and little trust in polls even if there were – there's no easy way to know whether or not that confidence is misplaced. How long will all of this take? Martin Gerten / AFP / Getty Images Assuming that there is some kind of challenge for the Labour leadership – whether or not Corbyn is on the ballot – the party's rules set out that the contest ends during the party's annual conference, where the winner is announced.Labour's conference this year will take place in Liverpool between 25 and 28 September. So settle in: There's another 12 weeks of this to come.