Schisms in both Labour and Conservative parties could add extremism to instability

A split in the Labour Party in the event of Mr Corbyn winning a leadership contest now seems all but inevitable and the prospect of a victory for Andrea Leadsom raises the possibility of the most dramatic realignment in British politics in decades

Friend or foe of Jeremy Corbyn, the constant destabilisation of the Labour Party hasn't been good for anyone (Reuters)

So, she isn't bluffing after all. After a seemingly endless wait for her to deliver on her promise to run for leader against Jeremy Corbyn, Angela Eagle is going for it. She may be followed by an announcement from the still-more obscure Owen Smith, one of those politicians who invites the old joke about not even being a household name in their own kitchen.

All of this is good. Friend or foe of Jeremy Corbyn, the constant destabilisation of the Labour Party hasn't been good for anyone, and least of all for a country crying out for political leadership and effective opposition.

That instability will not end quickly, however. Ms Eagle has made clear that she thinks Mr Corbyn will need to be nominated by 51 MPs, and that the National Executive Committee will have the final say on the rules. Naturally, Mr Corbyn disputes that. There is much talk of lawyers – which means lengthy proceedings may not be far away. The truth is that this is a political not legal question, and that Labour would be better off having Mr Corbyn beaten fair and square, rather than have his leadership ended in a way that his many supporters will never accept as legitimate. It would be difficult to prevent them from the mass de-selection of sitting non-Corbynite Labour MPs.

Who will win? Recent experience suggests that speculation about British politics is unusually hazardous these days. It seems clear, though, that Mr Corbyn retains a sizeable base of support, and that Ms Eagle, for all her dry wit, intellectual ability and attractively prosaic style may not be the person to unseat Mr Corbyn, though politics is full of surprises. He may well, in other words, win a fresh mandate.

Labour's old wounds over the Iraq War will be torn open again by the parliamentary debate on the Chilcot report and a Commons motion alleging Tony Blair to have been in contempt of parliament in the run up to the war. Mr Corbyn has indicated support for that, which may once again bolster his popularity among his grassroots, but do little to build confidence in his judgement among his MPs.

It all adds to a highly combustible mix, and a split in the Labour Party in the event of Mr Corbyn winning a leadership contest now seems all but inevitable. The prospect of a smaller breakaway among Conservatives in the event of an Andrea Leadsom victory also raises the possibility of the most dramatic realignment in British politics in decades. She is being talked up and the odds on her are shortening.

Will she – Ms Leadsom – win? She certainly does not deserve to do so. The most charitable interpretation of her "I'm a mum" interview is that she asked the journalist not to make her remarks about children too prominent in the presentation of the article. But that's all.

She has not repudiated her views, but merely expressed her mortification about the headline. She said what she said; it was on the record; it was no slip of the tongue. Her attitude is not only offensive, but nonsensical. Ms Leadsom has spectacularly failed to move beyond platitudes and offered her party and the wider country a single policy idea beyond scrapping employment rights in very small firms. She needs to demonstrate why she is optimistic about Britain's prospects beyond her faith in the British people.

How will she deliver a vibrant economy outside the single market, the largest and richest in the world? How will she protect inward investment? Find migrants to do the work people already here cannot or will not do? By the end of the year we may be treated to Prime Minister's Questions being asked by Mr Corbyn and answered by Ms Leadsom. These two unimpressive and frankly extremist figures who their respective MPs openly ridicule will be leading the national debate on Brexit, austerity, public services, the nuclear deterrent and much else.

For those who thought 2016 couldn't get any worse, just consider that thought.