The numerous strikes in the United Kingdom during the summer of 2022 gave rise to the use of the phrase summer of discontent.

This alludes to the phrase winter of discontent, of Shakespearean origin [cf. footnote], which is used to denote the winter of 1978-79 in the United Kingdom, during which widespread strikes took place in protest against the then Labour government’s wage limits; these strikes are widely seen as contributing to a change of government the following spring.

The connexion between 2022’s summer of discontent and 1978-79’s winter of discontent is clear in the following from ‘Stuff your 5%!’ Is the UK facing a summer of discontent—and what can we learn from the winter of 1979?, by Andy Beckett, published in The Guardian (London and Manchester, England) of Wednesday 20^th July 2022—read Andy Beckett’s article here:

Transport workers, barristers, doctors, teachers, nurses, civil servants: if they haven’t yet voted to strike, they’re likely to do so. The last time anything like this happened, it brought down the government…
The winter of discontent of 1978-79 happened so long ago. In some ways, Britain was very different then: in its familiarity with trade unions, its politics and work habits, its distribution of power and wealth. Some of the long-dead shop stewards and union leaders who led the walkouts that winter, and who considered what they were doing completely normal and justified, would probably be surprised that we are still talking about them.
But we are. For a lot of politicians, journalists, employers, trade unionists and voters, some of whom were not even alive when it happened, the winter of discontent remains a reference point: an infamous or celebrated episode, either something to repeat—a model for turning this year’s strikes into a “summer of discontent”—or something that must never happen again. In short, it is seen as one of the past half-century’s pivotal events.

But, in fact, the phrase summer of discontent has, in the course of time, been coined on separate occasions by various persons, independently from one another.

For example, in 2013, the British political columnist Dan Hodges (born 1969) frequently used this phrase in The Daily Telegraph and The Sunday Telegraph, two Conservative newspapers published in London. The following, for instance, is from The Sunday Telegraph of Sunday 11^th August 2013:

Earlier this week I was speaking to a shadow cabinet adviser about Ed Miliband’s ongoing summer of discontent.
A collapsing poll lead; MPs openly expressing concerns about their leader; shock and concern at David Cameron’s poaching of Barack Obama’s campaign supremo Jim Messina.

Among the early occurrences of the phrase summer of discontent are the following two:

1-: From a correspondence from London, published in The North Wilts Herald (Swindon, Wiltshire, England) of Saturday 1^st June 1867:

The London doctors generally are making loud complaints of the healthiness of the season. Their glorious winter, the busiest almost ever known, has been succeeded by a summer of discontent. I don’t think they are quite reasonable in their present grumble. They can’t eat their cake and have it too, they can’t kill their patients in January and cure them in May.

2-: From the Nottingham & Midland Counties Daily Express (Nottingham, Nottinghamshire, England) of Friday 18^th August 1882:

Whitebait dispatched on Wednesday at Greenwich, and the baiting of Ministers finished on Friday at Westminster—is not this a welcome relief to all concerned? The weather has taken up, the glass is again rising, and will probably continue to rise for the whole of August. So ends a Summer of discontent in a glorious Autumn. So dies down the last note of resistance to law and order in Ireland; so ends, let us add, the fears of some and the hopes of others of a break-up of the Ministry by a dissolution and an appeal to the country.

Note: The phrase winter of discontent, which more generally denotes a period of adversity or unrest, originated in the opening line of The Tragedy of King Richard the third (London: Printed by Valentine Sims, for Andrew Wise, 1597), by the English poet and playwright William Shakespeare (1564-1616):
—Richard, Duke of Gloucester, evokes the re-accession to the throne of his brother, Edward IV, eldest son of the late Richard, Duke of York:

Enter Richard Duke of Glocester solus.

Now is the winter of our discontent,
Made glorious summer by this sonne of Yorke:
And all the cloudes that lowrd vpon our house,
In the deepe bosome of the Ocean buried.
Now are our browes bound with victorious wreathes,
Our bruised armes hung vp for monuments,
Our sterne alarmes changd to merry meetings,
Our dreadfull marches to delightfull measures.