Workers at a Coca-Cola plant have begun a 48-hour strike after rejecting a below-inflation pay rise.
Coca-cola said supplies should not be hit by the strike
Union officials said the walkout at the firm's bottling and distribution centre in Wakefield, West Yorks, would have a "devastating effect" on supplies.
Colleagues at another Coca-Cola site in Milton Keynes, Bucks, are going on strike for 24 hours, from Friday morning, as part of the same dispute.
Coca-Cola said its customers could rely on supplies being maintained.
The Wakefield site is Coca-Cola Enterprises's largest bottling and distribution centre in the world.
It also produces other soft drinks including Oasis and Dr Pepper and supplies shops, supermarkets, vending machines and pubs across the UK.
Unite union said it was "furious" management offered to improve the 2.5% offer by asking workers to sacrifice overtime rates and bonuses.
Regional officer Davy Hall said: "While Coca-Cola Enterprises make significant profits, we are not prepared to see our members' wages cut.
"Their hard work has delivered the profits for Coca-Cola Enterprises. Their mortgages, gas bills and council tax have all increased but their pay has fallen flat.
"This is the first two days of strike action. We are prepared to reopen negotiations to help resolve the dispute but our members are also adamant that the dispute could well escalate."
About 100 workers based at the Wakefield site took to the picket line with banners, including one which read: "Strike - it's the real thing."
Technician Steven Tattersall, 38, from Barnsley, said: "A lot of staff feel as if they are not valued any more. People's standards of living have dropped."
The Wakefield operation, which produces 200m cans of Coke a week, employs 517 staff, including manufacturing and distribution technicians and local delivery drivers.
Workers at the Wakefield site are also banning overtime as part of their campaign of industrial action.
After the announcement of strike plans earlier this month, Stephen Moorhouse, vice-president for Coca-Cola operations in Great Britain, said the company's offer remained on the table.
He added: "We cannot justify a settlement of almost double the 2007 norm and feel this would be unfair to the rest of our associates across the rest of the British business.
"I'd like to reassure our customers that they can rely on us to keep delivering the supplies they need throughout the summer."
Another 48-hour strike is planned at the Wakefield site on 13 and 14 August.