Supermarket giant Sainsbury's has said it plans to close two Argos depots in a move that will impact 1,400 jobs.
It is expected to take place over the next three years as part of a wider shake-up of its general merchandise operations across the group that would see its major warehouses cut from five to three.
The company said it was proposing to close its Basildon distribution centre in Essex and depot at Heywood, Greater Manchester.
It said the move would also threaten support staff employed by Wincanton.
Sainsbury's said all its workers affected by the plan would have the opportunity to apply for jobs elsewhere in the company.
The Unite union responded by saying there was "no economic justification" for job losses, claiming at least 750 people would be left out of work by the decision.
Sainsbury's argued it had to modernise its logistics operations.
It had previously set out plans for a network of smaller, more localised, fulfilment centres.
The company's statement said it was looking to further automate operations at its Daventry site, "enabling a reduction of stock, more responsive delivery to customers and stores and a simpler delivery process for suppliers".
An office in Milton Keynes was also slated to be shut due to greater demand for flexible working.
The three remaining Habitat showrooms were also to be closed.
Simon Roberts, Sainsbury's chief executive, said: "As with any major change to our business, we have not taken the difficult decision to start this consultation lightly."
He added that it was vital that the group improved efficiency to invest in the customer experience.
But Unite national officer, Matt Draper, said: "Management at Argos/Sainsbury's has yet to provide any form of business case for the loss of these jobs.
"Unite will be fighting to preserve every job and will put forward an alternative business case to the company to preserve employment at these two sites.
"This is an incredibly wealthy company which should be investing in its loyal workforce rather than dumping workers in pursuit of short-term profits.
"If Sainsbury's doesn't drop its closure plans then Unite will pursue all avenues to preserve employment at these sites."