The fact that the Conservative Party achieved 9% of the European Parliament vote in Britain, and 3% of eligible voters, raises a serious question of the legitimacy of a selected new Prime Minister with executive power. If one is selected by hardly a cross-section fragment of the voting electorate to lead the United Kingdom towards a no deal exit from the European Union, then the House of Commons is within its rights to box in such a Prime Minister with immediate effect. It has to be done rapidly, by grasping legislative power to itself (failed by one vote, when it tried before) or indeed by a vote of no confidence that, under the Fixed Term Parliament Act, could transfer to an alternative executive power, tolerated for the specific purpose of legislating to remove our end of the crash-out date.
The break up of the United Kingdom is the consequent danger of a government crashing out as a hostile act against the House of Commons and the remain majority vote in the United Kingdom. Scotland, through the vehicle of the Scottish National Party, and Wales and Northern Ireland/ North of Ireland will not stand for being taken out of the EU against their will. The Conservatives may well end up not only destroying themselves, and our good relations within the EU, but also the fabric of the United Kingdom itself.
(Personally, I am in favour of a political settlement that has the UK functioning rather like the EU, in that the nations can be fully independent but come together with a Council of the British Isles. Even Ireland as a whole could be in this, for consultation and agreement. However, it is one thing to move harmoniously and in agreement to such an arrangement, and another to do it through incompetence and acrimony.)
Vince is going as a leader, in harmony, and that is right. He's taken the Liberal Democrats through lean times and now they are in the right place at the right time. I did not switch to the Liberal Democrats to uphold my wish for the UK to stay a full member of the European Union, but it has my vote anyway because adopting its remain policy after a short post-referendum wobble was always part of the Liberal Democrat DNA. Theresa May fell victim to the Tory knives, and in one sense the European Parliament election vote for the Tories was at last compatible with government incompetence.
Vince is in his seventies and Jeremy Corbyn has entered his seventy-first year. The Labour office early on showed an inability to run a smooth party machine. He won his leadership re-election, but in the end a small group of Labour MPs ran off to form Change UK. Corbyn continued to sit on the fence, a position not only derived from Conference policy - that needed long description - but where one could see his own reluctance, and also see leading members of Labour able to interpret the policy to the point of contradiction. When my friends claimed that Labour was a 'stay-in' party, I could easily ask, "Really?" and quote those who said otherwise. Such a stance, or lack of stance, reaped its lousy reward.
Thus the likes of both Alistair Campbell and Lord Michael Heseltine could vote Liberal Democrat, and many a socialist and those worried about the environment could vote Green (the latter reason implies the Member of the European Parliament will actually contribute towards European policy, whereas the Tory, some Labour and the Brexit parties would have it otherwise).
Neither the Labour Party nor the Conservative Party suggest competence; but, although I hated the Liberal Democrats propping up the Tories, at least one can say that the coalition was competent and did bring in Cabinet Government. The Liberal Democrats need to get past the First Past the Post tipping point and be in government on their own, or maybe with friendly partners or support picked up in these years.
People dismiss a Tory split - "they stick together" - but facing oblivion can facilitate a split and cause behaviour away from the tribal. A Labour split isn't beyond imagination either. I think a possibility here is for Change UK to pack up, and its ex-Tories take their social conscience and individualism into the Liberal Democrats. If the ex-Labour members don't want to go in with them, well, perhaps with the ex-Tories gone, they might combine with more leaving Labour MPs should Labour itself continue to sit on the fence. Politicians should not worry about shifting about more than once, so wrap up Change UK as a fast-failed idea. Change UK did cost the Liberal Democrats a couple of seats in the d'hondte system of allocation; not sure if UKIP had the same effect on the Brexit Party - it was NOT Proportional Representation. It was PR in Northern Ireland, if a bit chunky with three seats for a whole province. UKIP is having a leadership election again, as it falls into racist-dallying sectarian oblivion.
The Tories don't want to have a General Election before enacting leaving the EU. Well, tough. The government and Prime Minister lacks legitimacy, and so the immediate political future is for MPs to prevent a no deal. And crashing out is probable because the EU won't have its executive branch sorted out until too late for any negotiations. If a 'deal only' Prime Minister was to be selected, then it's back to the only deal the EU agreed - there isn't another - or it would need an extension again for a new one. Then the House of Commons would be back to the strategy it operated during the hapless years of Theresa May. Otherwise it must sharpen its act against executive power.