Workers at the UK's biggest container port will go on strike for more than a week later this month in a dispute over pay.
More than 1,900 members of the Unite union in Felixstowe will strike on Monday, August 21, from Monday to August 21.
The union said that Felixstowe Dock and Railway Company had failed to improve its offer of a 7% pay increase, after only a 1.4% increase last year.
Almost half of the UK's container traffic comes through Felixstowe and Unite said the action would affect supply chains, the logistics and haulage sectors, as well as international maritime trade.
It is the latest round of industrial action by workers pushing for pay to keep up with the cost of living.
Bobby Morton, a unite national officer for docks, said: Strike action will cause huge disruption and will cause massive shockwaves throughout the UK supply chain, but this dispute is entirely of the company's own making.
It has had every opportunity to make our members a fair offer, but has chosen not to do so.
Felixstowe needs to stop prevaricating and make a pay offer that meets our members' expectations. Sharon Graham, unite general secretary, said both the Felixstowe docks and its parent company CK Hutchison are hugely profitable and incredibly wealthy, adding: They are fully able to pay the workforce a fair day's pay.
The company prefers to pay its workers a decent wage rather than delivering multi-million pound dividends.
Unite will give the workers at Felixstowe its full support until the dispute is resolved and a decent pay increase is secured. There are more talks scheduled to take place on Monday.
A port spokeswoman said in a statement provided to media that the company continues to seek a solution that works for all parties and avoids industrial action.
We understand our employees' concerns about the rising cost of living and are determined to do all we can to help while continuing to invest in the port's success.
The company's latest position in negotiations is an increased pay increase of 7%, and the discussions are ongoing. We will have a meeting with Acas and the union on Monday 8 August.
The port hasn't had a strike since 1989 and we are disappointed that the union has served notice of industrial action while talks are ongoing. There won't be a winner from industrial action, because the port provides secure and well-paid employment. The Department for Transport has been contacted for comment.
Felixstowe welcomes approximately 2,000 ships a year, including some of the world's largest container vessels, according to its website.
Around 17 shipping lines operate from the port, offering 33 services to and from more than 700 ports around the world.