Ed Miliband is under pressure to condemn strike plans by the Unite Union, the Labour Party's biggest backer, which would disrupt the beer supplies for 30,000 pubs and bars across Britain next week.
Unite said it would launch a strike for "24 hours from 10.00 on Wednesday 11 September to 10.00 on Thursday 12 September", following an unresolved dispute with Kuehne and Nagel Drinks Logistics.
Deliveries of Foster's, Heineken, Kronenbourg, John Smith's, and Strongbow would be severely disrupted, with many outlets potentially running low on supplies.
Pubs run by Wells and Young’s, Enterprise Inns, Trust Inns and JD Wetherspoon would be worst affected with airports, with sports clubs, theatres and cinemas also suffering.
Unite national officer Rhys McCarthy said "KNDL's refusal to take our concerns seriously means there will be significant disruption to the supply of beer right across the country."
"Whether it's the Houses of Parliament, Manchester City football club or your local Wetherspoons' pub there will be serious consequences."
"We have tried to engage with the company but it has repeatedly refused to resolve this dispute."
The strike was called for after claims that changes KNDL could lead to job losses, with 85% of union members voting in favour of the move.
Community pubs minister Brandon Lewis said: "This is a national disgrace. Labour's biggest union paymaster is hitting at the right of hardworking people to have a pint after a day's work."
"In contrast, Conservatives have knocked a penny off a pint. We have also scrapped Labour’s beer duty escalator, which was bankrupting community pubs."
"Ed Miliband must condemn this strike; if he’s too weak to stand up to his union bosses, he’s too weak to stand up for hardworking people."