Ocado shares have dropped 6% and the retailer has warned of a hit to sales following a huge fire which swept through its warehouse in Hampshire.
About 200 firefighters spent the night tackling the blaze, which broke out on Tuesday morning.
The online grocer said it expected a fall in sales growth until it could shift operations to other warehouses.
More than 30,000 orders are processed by robots at the Andover warehouse each week.
Ocado has not given any detail about what the impact will be to customers.
Many customers have contacted Ocado on Twitter to ask about cancelled deliveries, while others have expressed sympathy for the online supermarket.
Operations at the 30,000 sq m complex remain suspended.
Ocado has other warehouses, including in Hatfield, Hertfordshire, which have been unaffected.
The site, on the Walworth Industrial Estate, accounts for 10% of Ocado’s capacity.
Ocado said it had comprehensive insurance for the property, stock and equipment and for business interruption losses.
“Once we have had time to assess the damage and prepare a plan to return the CFC (customer fulfilment centre) to operation we will update further as appropriate,” a spokesman said.
Hampshire Fire and Rescue Service said about 70 firefighters remained at the site and urged nearby residents to keep doors and windows shut.
Chief fire officer Neil Odin said the initial small fire had taken a “dramatic turn” early on Wednesday morning and firefighters had to be withdrawn.
“This building is not meant for humans to be interacting with the racking and the storage – it has robots moving racking on to loading bays, so for firefighters trying to get in that high and to make an effective fire-fighting strategy, it has been very difficult,” he said.
Four firefighters have been treated for minor smoke inhalation.
No Ocado staff were injured in the blaze.
On Tuesday Ocado said it had cancelled some customer orders because of the fire and it was “working hard to resume normal service as soon as possible”.
The blaze came on the same day it reported widening losses.
The company recorded a pre-tax loss of £44.4m for the year ending 2 December 2018, compared with £9.8m in the previous 12 months.