A no-deal Brexit threatens the UK's food security and will lead to higher prices and empty shelves in the short-term, retailers are warning.
Sainsbury's, Asda and McDonald's are among those warning stockpiling fresh food is impossible and that the UK is very reliant on the EU for produce.
The warning comes in a letter from the British Retail Consortium and is signed by several of the major food retailers.
It comes ahead of crucial votes in Parliament on Tuesday.
The letter from the retailers, and seen by the BBC, says there will be "significant risks" to maintaining the choice, quality and shelf life of food.
"We are extremely concerned that our customers will be among the first to experience the realities of a no deal Brexit," the letter says.
MPs will consider a series of amendments to Theresa May's plans that could shape the future direction of Brexit.
While it will not be MPs' final verdict on the deal, they will vote on the amendments and, if one is passed, it will illustrate what changes to the deal might be enough to get a modified version of the deal through Parliament.
Retailers have been reluctant to intervene in the Brexit debate but are doing so now as the UK's departure date from the EU approaches.
In the letter, they urge MPs to work together "urgently to find a solution that avoids the shock of a no-deal Brexit".
The letter uses the government's own estimate that freight through Calais may fall 87% from current levels, threatening the availability and shelf life of many products.
It expresses worry over tariffs, with only 10% of the UK's food imports currently subject to World Trade Organisation (WTO) rules.
If the UK were to revert to WTO rules, the retailers warn that would "greatly increase import costs that would in turn put upward pressure on food prices".