Thousands of UK workers have gone on strike or threatened to this summer, including rail workers, airport staff, telecoms workers, barristers and postal workers.
Multiple walkouts risk causing widespread disruption to the public and could have a knock-on effect on consumer demand, businesses warn. But unions say they have no choice.
Why are the strikes happening?
Unions say wages are not keeping pace with the rising cost of living and their members need a pay rise.
Inflation - the rate at which prices rise - is currently at a 40-year-high of 9.4% and the Bank of England has warned it could reach 13% as energy, fuel and food prices soar higher.
The Trades Union Congress (TUC), which represents 48 affiliated unions with about 5.5 million members, has called for a "decent pay rise for public sector workers" and a £15 minimum wage across the board.
It said its research suggested workers have lost almost £20,000 since 2008 because pay has not kept pace with inflation.
General secretary Frances O'Grady told BBC News that ordinary working people were saying "enough is enough" after over 10 years of stagnant wages.
Unions also say workers are facing cuts to terms and conditions and the threat of redundancy.
The National Union of Rail, Maritime and Transport Workers (RMT), for instance, wants Network Rail and 14 train operating companies to guarantee that its members won't face jobs cuts or "drastic changes" to work patterns.
It wants a pay rise to "tackle the cost of living" - one that could potentially be higher than 7%.
Some 40,000 of its members held three massive strikes in June and further walkouts were planned later in the summer.
Who is threatening to strike?
- More than 40,000 workers at telecoms giant BT will take part in two 24-hour strikes in a row over pay. The strikes will take place on 29 July and 1 August according to the Communication Workers Union.
- Barrister strikes in July suspended criminal trials in many courts across England and Wales. The Criminal Bar Association wants at least a 25% pay rise for its members.
- Royal Mail managers will "work to rule" between 15 and 19 July the Unite union said, refusing to take on any additional duties to slow down productivity. The managers will also hold walkouts between 20 and 22 July.
- Separately, the Communication Workers Union are balloting postal workers until July 19 - they are calling for a wage increase of up to 9.1% in line with inflation.
- The RMT Union has said it will strike repeatedly until the end of 2022 until the demands of railway workers are met.
- Separately train drivers at eight rail companies will strike on 30 July in a dispute over pay, union Aslef has announced. The date coincides with the Commonwealth Games, which are being held in Birmingham. It is also the first day of the English Football League season.
- Hundreds of Transport Salaried Staffs Association members at Southeastern trains have also voted for strikes.
- Hundreds of British Airways staff at Heathrow Airport who are members of the GMB union are voting in a pay ballot which closes on 21 July. This could lead to strikes.
- The biggest teaching union, the NEU, and the National Union of Teachers want a 12% pay rise for members and will "strongly" encourage them to join industrial action over autumn if negotiations fail.
- Unison, which has almost half a million members working for the NHS across the UK, said some of its members in the South West plan strikes over pay in July.
- Doctors represented by the British Medical Association are calling for a 30% pay rise over the next five years to make up for real-terms reductions in their salaries. Nurses want 12% or more. No strikes have been called but it raises the likelihood of action.
What do employers and the government say?
Business and public sector employers who were hit hard by the pandemic say they have to make modernising reforms as their costs rise and consumers spend less.
They also accuse unions of refusing to compromise at a time when they know workers are in short supply in some industries.
After the RMT announced its strike for July, Network Rail boss Andrew Haines said the union's plan was "incredibly frustrating" - "even more so" given the union hadn't put the latest pay offer to members.
He added that Network Rail could only fund higher wages by "modernising" working practices.
The government has also warned against employers handing out big pay rises over fears of a 1970s-style "inflationary spiral". That's where firms hike wages and pass on the costs to consumers via higher prices.
A Treasury spokesman added: "As part of our £37bn support package we're saving the typical employee over £330 a year through the imminent National Insurance tax cut, are allowing universal credit claimants to keep £1,000 more of what they earn and have made the biggest cut to all fuel duty rates ever."