Workers who deliver beer, lager and soft drinks to pubs, clubs - and Downing Street - will stage a 24-hour strike tomorrow in a row over jobs.
Unite said the walkout by its members at Kuehne + Nagel Drinks Logistics (KNDL) from 10am would cause 'significant disruption' to thousands of sites.
Pubs, clubs, airports, theatres, mainline railway stations, football grounds and Parliament will all be hit, said Unite.
The union said a restructuring exercise, including three new 'super hubs', will lead to job losses.
Unite national officer Rhys McCarthy said: "KNDL's refusal to take our concerns seriously mean there will be significant disruption to the supply of beer right across the country.
"Unite cannot rule out further action if the company continues to drive through change without properly negotiating or assessing the impact these changes are having.
"Our members are already bearing the brunt of complaints from customers because of the company's changes. They are proud of their jobs and they know that the previous system for delivering beer worked and customers were happy.
"The changes being pushed through will not work. They will eventually lead to job losses and will cause enormous problems with deliveries to customers.
"Hopefully when we next meet to try and resolve this dispute, KNDL management will begin to negotiate seriously."
The company said it had contingency plans and would seek to minimise disruption to deliveries.
The firm added it had been consulting employees for a number of years over the need to adapt its business model.
Picket lines will be mounted at depots across the country.