In May 2017, British Conservative prime minister Theresa May called a snap election three years early, despite having a comfortable majority in Parliament and having told the country she would not do so.

May was polling well and assumed it would be easy to push Jeremy Corbyn's Labour opposition to a crushing defeat, winning an even bigger majority that would strengthen her hand in Brexit negotiations. Most pundits agreed this was the likely outcome.

But on polling day, May failed dismally. The Tories lost their majority. Corbyn, despite having faced bitter opposition from within his own party since being elected leader two years earlier, somehow managed to reach out over them to speak to a much wider public.

Something had happened to the body politic that had been missed by the media. Now, with the announcement of Corbyn and former Labour MP Zarah Sultana's new party, a similar shift is underway - and is once again flying under the radar.

As I wrote for openDemocracy at the time, back in 2017, Corbyn was drawing large crowds across the country ahead of the election. When his rallies and meetings were held in public spaces, thousands turned up, often at short notice. If scheduled for indoor venues, these would be full to bursting, and he often had to repeat his speech to those waiting outside.

In one sense, there had already been signs of something going on below the political surface. When Corbyn first ran for the party leadership in 2015 - a contest in which he was the runaway winner - there were early indications that he was attracting considerable support from the grassroots.

A year later, strong opposition from within his own party led to a leadership challenge that he won, again achieving a hugely positive reaction at public meetings in spite of his internal critics.

History is repeating itself. Corbyn and Sultana's new left-wing offering - not yet officially named but for now known as Your Party - may be a work in progress, but the enthusiasm with which it has been greeted is palpable.

Some 800,000 people have signed up to support the idea. If just a quarter follow through to become members when it is formally established, it may well become the UK's largest political party by membership overnight, given the collapse in Labour membership.

The idea that a new decidedly left party could come to the fore and acquire serious political power may seem impossible, given Westminster's First Past the Post voting system, but just look at what is happening across the UK political scene, especially in England.

It's hard to say how many groups have sprung up across the country to form local concentrations of support for Your Party in the past four or so weeks, but it almost certainly runs into the many hundreds. In the West Yorkshire council where I live, two groups have already met, with two more due to do so in the next week, all with loose coordination yet covering the whole area of the metropolitan council.

In contrast, Labour's practised and experienced membership bureaucracy is seeing support ebbing away. Accurate, up-to-date figures are not easy to come by, but the party reportedly had 309,000 members six months ago, down from a peak of 532,000 under Corbyn in 2019. Some constituency party treasurers are reporting recent membership losses of up to a third over the past year alone.

There are many factors involved in this decline, not least the Labour leadership maintaining a marked degree of austerity and failing to confront Nigel Farage and Reform UK head-on. But perhaps the key problem is the party's even greater failure to confront Benjamin Netanyahu and his Israeli government over the appalling genocide they are inflicting in Gaza. This issue, probably more than any other, is leading Labour activists who would normally be at the forefront of projecting its policies to leave the party in droves.

Can Labour's decline and Your Party's rise, not to mention the current considerable strength of Farage and Reform UK, lead to a radical re-ordering of the political environment in England? Several things suggest it could be possible.

For a start, we're likely three years away from a general election being called. That gives enough time for Reform's weaknesses to show themselves.

The party is substantially trading on fear, principally of migrants, but which commonly extends to a more general 'fear of the other'. Corbyn is particularly effective at countering this head-on with hope, which is thoroughly appealing and especially so to younger people, as can be seen in new polling showing that one in five 16 and 17-year-olds would vote for Corbyn and Sultana's new party.

Reform is also vulnerable in its attempts to claim it is standing up for the ordinary person against a woke and distant elite. That simply doesn't add up; given the considerable wealth floating around the Reform leadership and its funders, it is not difficult to present them as the true elite.

Finally, a serious weakness for Reform and the Tories is their Cnut-like denial of climate breakdown and their addiction to fossil carbon. The folly of that stance may well come to haunt them over the next three years, as more and more ordinary people across the UK experience floods, or wildfires, or other climate crisis-related weather phenomena.

Then there is the other side of the political scales, starting with the election this week of Zack Polanski as the Green Party leader. Polanski has not yet ruled out working with Sultana and Corbyn, and there is time for local electoral pacts to be negotiated in forthcoming elections, especially the many local elections and the Scottish and Welsh national elections taking place next May.

We also should not discount the Liberal Democrats, who have considerable geographical concentrations, north and south of the border. In Scotland, in particular, there are plenty of new, younger politicians coming through, just as there are in the Scottish National Party. Your Party is also likely to lead to the emergence of new political figures on the progressive left in the coming months, while others may decide to defect from Labour to the party.

A couple of other elements are worth watching, too. Sultana, Polanski and Corbyn are all highly committed politicians and very effective communicators. Expect to see a lot more of them, even on the legacy media.

Of them, Corbyn is key. He is not remotely a rabble-rouser, yet for the past ten years, he has maintained a formidable and dedicated network of supporters - even at very difficult times. It is very easy to dismiss what he stands for as being from the past, but perhaps it is actually from the future.

From openDemocracy