Hundreds of Amazon staff have gone on strike as people take advantage of Black Friday, one of the year's busiest shopping days.
Members of the GMB union are locked in a pay dispute with their employer and are on the picket line outside the firm's Coventry site.
Strikes are also taking place in Europe and the US - unions say it is the biggest walkout in Amazon history.
Amazon said the industrial action would not affect customers.
Staff in Coventry were the first of Amazon's employees in the UK to strike when they began industrial action in January.
The GMB Union said more than about 1,000 workers were taking part on Friday.
The company recently announced it would increase the minimum starting pay to up to £13 an hour from April, depending on location, but the union has called for a rate of at least £15 as well as better working conditions.
Speaking at the picket in Coventry, GMB senior organiser Stuart Richards said the offer from Amazon "isn't enough".
"They [the workers] deserve better than this. They deserve a decent amount of pay from a company that makes huge amounts of profit," he said.
Mr Richards said there were union members taking action in five different countries, including Germany, the United States and Italy.
He added: "This is now a global wake-up call for Amazon. They can't keep ignoring the concerns of these workers and the workers in warehouses across the world.
"It's clear that this is a huge momentous thing that Amazon just needs to listen to."
An Amazon spokesperson said the firm regularly reviewed its pay "to ensure we offer competitive wages and benefits".
"By April 2024, our minimum starting pay will have increased to £12.30 and £13 per hour, depending on location - that's a 20% increase over two years and 50% since 2018," they continued.
"We also work hard to provide great benefits, a positive work environment and excellent career opportunities. These are just some of the reasons people want to come and work at Amazon, whether it's their first job, a seasonal role or an opportunity for them to advance their career."
The strike comes two days after the Chancellor Jeremy Hunt's Autumn Statement included an announcement that the National Living Wage is set to rise from £10.42 to £11.44 per hour, from April.
Amazon said its pay was above that level already, as well as being higher than the voluntary Real Living Wage, which stands at £12 an hour for workers outside London. It added that it also offered other benefits.
