In recent days, a number of unexplained chalk graffiti tags have been seen in various places across Croydon.

The tags, most of which simply read '3.5', '3.5 per cent' or 'Resist', have been pictured on pavements, walls, trees and a lot of other surfaces besides in Croydon in recent days.

So what's going on?

The reason for the mass graffiti is linked to the ongoing crises in the UK, and non-violent resistance against the government.

The Croydon Guardian spoke with Historian Paddy Docherty, who highlighted the appearance of the 3.5 per cent tags in Croydon recently, to find out more.

"I’ve been astonished at the way 3.5 per cent has spread so quickly, and so widely," he said.

"It’s been amazing to see chalkbombing happening all over the country, and I’ve even been sent pics of people chalking up their car, and embroidering it onto a tote bag, putting it on facemasks," he added.

Indeed, as well as Croydon, 3.5 per cent "chalkbombing" campaigns have been seen across the UK from Edinburgh to Eton.

Docherty explained that the campaign, which he supports and helped get off the ground, is linked to the work of US scholar from Havard, Erica Chenoweth.

Chenworth co-authored a renowned study on resistance to authoritarian governments which showed that when just 3.5 per cent of a country's population join in protests against their government, those protests succeed.

In Docherty's opinion, the UK government's response to the coronavirus pandemic, the climate crisis, Brexit and a number of other urgent issues has stoked the fires of such resistance in Britain today.

"It’s an incredible series of autonomous actions, which is why it’s so powerful," he said.

"It’s entirely organic and autonomous, which shows that many people feel incredible frustration at the state of our politics, and the failing of our systems of accountability."

Regarding Chenworth's thesis itself, Docherty suggested he was not best placed to critique it directly but had found the study very convincing.

"I find it extremely persuasive, not least because we have seen it happen many times – South Korea in 2017, the Orange Revolution in Ukraine, Romania 1989 etc," he said, pointing out the success of non-violent protest movements in those countries.

"The precise number of protesters isn’t the crucial thing, the important point is that it isn’t that many of the population. As Chenoweth says, peaceful and sustained protest is key, that’s what is most effective," Docherty pointed out.

One stumbling block in the UK however could be a lack of historical precedent of a victory of such a widespread non-violent campaign.

While social movements in the 1800s like the campaign for universal suffrage and the Chartists had massive impacts on British social life, they did not directly topple the governments they protested or achieve any of their central aims directly during the period they were active.

In contrast, the Suffragettes' campaign for Votes For Women, which did use violence, succeeded alongside the non-violent suffragists in achieving their central aims in a shorter timespan.

Nevertheless, Docherty suggested that such a collection of crises from the impending climate collapse to the likelihood of a 'No Deal' Brexit could sew the seeds of such a movement in the UK.

Indeed, that is what those who support the 3.5 per cent campaign in Croydon and across the UK expect.

"Once No Deal kicks in from January next year, with its job losses and food shortages, the government will be very vulnerable," Docherty suggested, anticipating the likelihood of the UK failing to reach a withdrawal agreement with the European Union in 2020.