Ocado said it has been forced to cancel some customer orders because of a huge fire that swept through an robotic warehouse in Hampshire.
The online supermarket said it was "working hard to resume normal service as soon as possible".
It comes after around 200 firefighters had been tackling a blaze which broke out at 2.44am on Tuesday morning and spread overnight, causing substantial damage.
Hampshire Fire and Rescue Service (HFRS) said "four of its firefighters had been treated for slight smoke inhalation" as they battled to bring the inferno under control.
Locals were urged to keep their windows and doors shut due to the smoke from the blaze, while the public was also asked to avoid the area.
The online grocer has seen shares slump after it warned over a hit to sales following the blaze.
The group’s shares dropped 6% as it said it would see a fall in sales growth until it can shift operations to other warehouses following the fire at its Andover site, which took more than 24 hours to get under control.
Ocado said the hi-tech robotic warehouse in Andover provided around 10% of its current capacity and its shutdown means there will be a "constraint on our ability to meet our growing customer demand".
It added: "There will be a reduction in sales growth until we can increase capacity elsewhere."
The HFRS confirmed: "About 200 firefighters were involved in tackling the fire which broke out at 2.44am on February 5."
"The fire in the robot-run distribution centre is now under control and it is no longer a major incident," the fire service added.
Ocado said part of the roof collapsed overnight, but it confirmed no members of the Ocado team or the public were injured.