Workers at the port of Felixstowe are to strike for eight days later this month in a dispute over pay.
Members of Unite will walk out on August 21 after talks at the conciliation service Acas failed to resolve the row.
Unite said more than 1,900 workers at Felixstowe, the country’s biggest container port, will be taking industrial action.
The strike was called after Unite said the Felixstowe Dock and Railway Company failed to improve on its offer of a 7% pay increase, describing it as “significantly below” inflation.
“The company has prioritised delivering multi-million pound dividends rather than paying its workers a decent wage.
“Unite is entirely focused on enhancing its members’ jobs, pay and conditions and it will be giving the workers at Felixstowe its complete support until this dispute is resolved and a decent pay increase is secured.”
The workers undertake manual roles at the docks including crane drivers, machine operators and stevedores.
Unite national officer Bobby Morton said: “Strike action will cause huge disruption and will generate massive shockwaves throughout the UK’s supply chain, but this dispute is entirely of the company’s own making.
“It has had every opportunity make our members a fair offer but has chosen not to do so.
“Felixstowe needs to stop prevaricating and make a pay offer which meets our members’ expectations.”
Further talks are scheduled to take place at Acas next Monday.
A company spokesperson said: “The company continues to actively seek a solution that works for all parties and that avoids industrial action.
“We understand our employees’ concerns at the rising cost of living and are determined to do all we can to help whilst continuing to invest in the port’s success.
“Discussions are on-going and the company’s latest position in negotiations is an enhanced pay increase of 7%. We are meeting again on Monday August with Acas and the union.
“The port has not had a strike since 1989 and we are disappointed that the union has served notice of industrial action while talks are ongoing.
“The port provides secure and well-paid employment and there will be no winners from industrial action.”
A Department for Transport spokesperson said: “We are aware of ongoing pay discussions and a decision to strike for eight days at the Port of Felixstowe.
“This action by the union runs the risk of disrupting the delivery of vital supplies and freight, and we urge the union and Port to remain at the table and agree a settlement.
“We remain in close contact with the port on the potential impacts on port operations and supply chains.”
Tim Morris, CEO of the UK Major Ports Group which represents the nine largest UK ports, said: “Unite’s announcement of significant potential strike action at Felixstowe is very unwelcome and deeply disappointing.
“Whilst the inflationary pressures we are all under are clear, ports are part of cost sensitive global supply chains and, as the Bank of England has forecast, the economic outlook is challenging.
“The UK has a broad network of ports and supply chains have learnt to adapt to significant disruption during the pandemic and Brexit.
“But potential strikes of the scale announced by Unite mean disruption can’t be ruled out. We note that talks between Felixstowe and Unite are ongoing with the support of Acas.”