More than 100,000 UK postal workers begin holiday season strikes

London(CNN Business) Postal workers in the United Kingdom are walking out during the busiest period of the year to demand higher pay as cost-of-living pressures mount.

As many as 115,000 Royal Mail staff went on strike on Thursday to demand better pay and working conditions. It was the first of 19 days of strikes planned to coincide with the peak holiday shopping season, including Black Friday and Cyber Monday.

The strikes are due to take place through early December, and follow walkouts in August and September. Parts of Royal Mail's service will be out of action for several days at a time as different teams walk out.

The Communication Workers Union, representing the workers, said in a Tuesday press release that the walkouts were part of the "biggest ongoing strike of the year."

The CWU said it is fighting Royal Mail's plans to change terms and conditions including the introduction of new performance standards and an increase in hours for new staff. The union also said the company had imposed a 2% pay increase on workers, well below the rate of inflation. It is pushing for more, though it has not said by how much.

"Postal workers are facing the biggest assault on their pay, jobs, terms and conditions in the history of Royal Mail," Dave Ward, the CWU's general secretary said in a radio interview Thursday that the union posted on Twitter.

Royal Mail has said that most letters will not be delivered on strike days, and customers should expect delays to parcel deliveries. It would deliver as many tracked parcels and those tagged for fast-track delivery as possible on strike days, the company added.

A Royal Mail spokesperson told CNN Business on Thursday that the strike action was "weakening [its] financial position."

"We are doing all we can to minimize any delays and keep people, businesses and the country connected," the spokesperson said.

The strikes are the latest in a wave of industrial action in the United Kingdom this year. Rail staff, bus drivers and lawyers are among the groups of workers who have walked out to demand higher pay as soaring inflation savages living standards. Amazon (AMZN) workers are being balloted on strike action, with the result of the vote expected next week.

UK consumer prices shot up 9.9% in August from the year before, hovering around 40-year high inflation of 10.1% recorded the previous month.

And the squeeze is only getting worse. Prime Minister Liz Truss' plans to push through billions worth of unfunded tax cuts sent the value of the pound plunging and the yields on government bonds soaring.

That's already pushing up mortgage payments as lenders price in more aggressive rate hikes by the Bank of England to tackle the inflationary impact of the tax cuts and weaker pound.

It's not just UK workers that are fed up.

In France, striking workers have blockaded ExxonMobil and TotalEnergies fuel refineries for several weeks in a dispute over pay, disrupting supply to thousands of gas stations.

On Wednesday, the French government took the extraordinary measure of ordering some staff at an ExxonMobil refinery in Normandy back to work. The rarely used measure can be imposed by the government when the country's national security is deemed to be at risk, and it could be more widely deployed in the dispute if agreement isn't reached soon.

In the United States, too, the threat of a rail strike that could further disrupt struggling supply chains has reemerged. Earlier this week, a union of railroad track maintenance workers rejected a tentative agreement with freight carriers over a lack of paid sick leave.

A rail strike by more than 50,000 railroad workers was narrowly averted in September after unions and employers came to a tentative deal on pay.

— Hanna Ziady, Chris Isidore and Vanessa Yurkevich contrbuted reporting.