Is the past year's spike in strike action here to stay?

Over the past 12 months, a historic wave of industrial action has swept the UK. As a new documentary series follows union leaders up close, the BBC's economics editor asks whether this surge in strikes is likely to persist.

"Listen, don't fall out with each other. Don't fall out with each other. It's really important everybody sticks together," says Sharon Graham, Unite's general secretary, as tensions flare on a bus drivers' picket line.

The Abellio drivers in two south London depots had been offered a 12% pay rise and a £500 bonus - splitting opinion among drivers, who had been striking without full pay for 10 days.

One driver later says: "The union rep, they're selling us out… there's a lot of traitors around."

Others say: "We got screwed" and "we've been here for two months freezing and we're dying". They would eventually win an 18% rise.

Settlements such as this one have been occurring in so-called shortage sectors, such as driving buses, lorries, and rubbish trucks, since the beginning of last year. Many of those settlements went under the radar, in very local disputes or even, as here, in individual depots.

The past year across industry and public services has seen hundreds of ballots, hundreds of thousands on picket lines, dozens of negotiations, double-digit pay claims and awards, and major legal battles between the government and public sector unions.

Only 15 months ago, No 10 were slapping down the governor of the Bank of England for saying that people should not ask for excessive pay rises. Four months before that, the then-prime minister was celebrating the prospect of a high-wage Britain for all.

And this time last year Ms Graham, the general secretary of the biggest private sector union, had never done a broadcast interview in that role. She and her colleagues are now household names after promising a "summer, autumn, spring and winter of discontent".

With access to top union leaders, the two-part documentary follows internal machinations at Unite, RMT and the RCN, as well as the GMB's campaign to win recognition at Amazon in Coventry.

Watch now on BBC iPlayer (UK Only). The first episode will be on BBC Two at 21:00 on 25 May, with the second a week later.

Part of Boris Johnson's survival strategy had involved squaring up to the unions over their pay claims and seeking to direct blame towards the Labour Party.

But the unions calculated that the old pattern of mutually dismissive relations between organised labour and government had altered since the pandemic and in the shared pain of a common cost of living crisis. The last year raises questions not just about that relationship, but whether something has changed in the water in the way the UK thinks about industrial relations.

Looming over all of this are the restrictions on ballots in the government's anti-union laws. The documentary shows how unions have got around restrictions requiring postal ballots and high thresholds on turnout.

The pattern over the past year has been unions breaking down national disputes into a series of far smaller local and sectoral ones, for which it is easier to win ballot mandates. Action is then co-ordinated across localities on the same day, giving the impression of massive national or regional walkouts, as with bus drivers across London.

The other pattern is that of the private sector settling high wage claims in areas of labour shortages.

Unite has a unit of forensic accountants assessing the profits and available cash flow of the parent companies, often foreign-owned, of the employers involved in disputes. In this case the owner was effectively the Dutch state (though it has now sold its stake), a fact routinely used by the union in online campaigning.

The experience in the public sector has been different. This time last year, there was no negotiation. The Pay Review Body process had recommended a settlement of around 3% across public services. This was often before the spike in inflation to double digits following the Ukraine war.

Prime ministers Boris Johnson and Liz Truss dug in on the issue. At first, so too did the Sunak administration, fearful of the fiscal cost and inflationary potential of significant rises in the wage costs of state employees.

The cameras were with Royal College of Nursing (RCN) General Secretary Pat Cullen ahead of the first strikes in its history.

The RCN itself had been asking for a 19% rise for nurses. The government said at that time it could not shift from the recommendation of the Pay Review Body and was not negotiating.

"It's never, ever going to get a resolution to this dispute," Cullen said later. "The last meeting that I had with the secretary of state, he arrived accompanied by five men and it was not a pleasant meeting. It was quite a bullyish conversation." Cullen said nurses had concluded that they were being treated differently because "we are 90% female".

And she said a government minister had told her in a meeting that they were surprised nurses needed to live off their salaries: "And you know, ministers coming into the room saying to me that they're shocked that nursing staff may be the main breadwinner in the family. Because they believe that it's a second salary that we don't depend on. They are totally out of touch."

The Department of Health said it did not recognise the claim and had "utmost respect" for all staff.

Nurses in the RCN in the end rejected the deal recommended by their own union - a sign of how strongly a large swathe of public sector workers felt about the squeeze in their real wages.

The film shows how nurses felt emboldened by large-scale public sympathy, especially since the pandemic.

This perception of support, even in less popular professions than the NHS, has helped underpin double-digit pay claims. The successful tactics in the private sector of balloting first for strike action in order to gain negotiating leverage in pay disputes has also spread to the public sector.

Some union bosses also acknowledge that in an era where more workers can work from home, the strikes may not have disrupted the public as much. While the overall number of strikes has not been seen for a generation, the total number of days lost to strike action is nowhere near the highs of the 1970s.

Nonetheless, some in the union movement are trying to push into new territory too, such as the GMB at Amazon.

Outside the company's Coventry warehouse, Stuart Richards, a senior GMB organiser, is attempting to recruit new members.

A US training video cartoon for Amazon managers leaked in 2018 certainly made clear that "we do not believe unions are in the best interest of our customers, our shareholders, or most importantly, our associates" - its term for workers.

But the staff arriving by car have been squeezed hard by the cost of living crisis - one tells of having to pawn a wedding ring - and some were willing to U-turn near the entrance to their workplace and sign up to Richards' campaign.

Eventually the GMB get more than half the Coventry workforce, which the union estimates at 1,300 in total, and serve a letter demanding recognition from the Amazon bosses - it is the first site in the UK to do so, after a decade of trying.

So the question really is whether the current spike in strike activity is entirely a reaction to rampant inflation or whether this is something that might have a longer-lasting impact.

The full data is not yet available, but it is difficult to escape a pattern of unionised workplaces, especially in shortage occupations, getting double-digit pay settlements.

They have responded to existing strike restrictions by moving to immediate localised ballots, even before starting negotiations. On the other hand, insiders say that membership spikes during pay disputes, but then falls back when pay deals are done. Union subs are another expense during a cost of living crisis. Official figures will come next year.

There are some concerns, though, about the persistence and stickiness of inflation. Even the Bank of England, which began last year warning about excessive pay rises, now couples that message with concerns about corporate pricing and profits, a similar message to that pushed by some union leaders.

And the political economy of all this does appear to be changing.

Bashing the unions has proven tricky for the government over the past year. David Cameron's union tsar Lord Richard Balfe argues that PMs Johnson and Truss should have sued for peace with public sector workers much earlier. The opposition felt confident enough to announce it would repeal the new "minimum service level" laws as well as older restrictions on ballots, if it wins power.

This current wave of industrial action appears to be calming, but is not yet over. The government is trying to settle pay deals it had previously left to Pay Review Bodies. Inflation may also now be falling sustainably. But the shadow of this year of industrial action may linger for some time.