Britain's farmers and food suppliers are begging the government for Brexit answers.

With just five weeks to go until Britain leaves the EU, businesses across the food supply chain say they remain in the dark about how they should operate in the event of no deal.

Nobody knows yet what tariffs will be applied on goods both leaving and entering the U.K. — though an announcement on that could come as early as Friday.

In Calais and Dover, no new infrastructure has been built to prepare for customs checks should controls be required. London has yet to provide exporters and importers any clarity around its proposed trading regime with countries outside the EU. And companies from supermarket chains to big food processors such as Nestlé say they have no idea what labeling requirements will be in place should no deal be reached.

“Obviously as importers of food, it’s really important that we know if there will be tariffs applied and if so what that is going to look like,” said Andrew Opie, director of food and sustainability at the British Retail Consortium, which represents supermarkets in the U.K. “There are a number of countries such as Iceland, Norway and Mexico — important for imports of food — where we are still uncertain what the trading arrangements will be on day one of a no-deal Brexit."

A lack of trading schedule means that supermarkets such as Tesco, Asda and Sainsbury’s still have no idea where they should buy from if there is no Brexit deal.

Nearly one-third of the food eaten in the U.K. comes from the EU.

This concern is particularly acute as Britain produces very little fresh fruit and vegetables in the months of March and April. At this time of the year, 90 percent of lettuces, 80 percent of tomatoes and 70 percent of soft fruit is sourced from the EU. Environment Secretary Michael Gove told attendees at the annual National Farmers Union conference this week that an announcement on the U.K.’s tariff schedule in the event of a no-deal could come out as early as this week.

Moreover, Opie said that the level of uncertainty means there is no guarantee retailers and food processors could send products into Ireland, as meat plants exporting into the EU have still not been registered. In addition, meat labeling to assure health and safety standards has still not been designed.

Last month, the chief executives of 12 retailers, including Marks & Spencer, Waitrose and Lidl wrote to lawmakers in the House of Commons to remind them that nearly one-third of the food eaten in the U.K. comes from the EU. They said the level of uncertainty has led to a considerable amount of stockpiling. But now, “all frozen and chilled storage is already being used and there is very little general warehousing space available in the UK,” they wrote.

Uncertainty is also acute for sheep farmers. Lambs entering British abattoirs for slaughter now will arrive at their destination in the EU after Brexit, meaning farmers aren't sure their product will even reach its final destination should labels fail to be recognized.

“What meat stamps will be recognized in the EU?” asked Phil Stocker, chief executive of the National Sheep Association. “One or two traders I’ve spoken with have said trade is already being dampened … People here and at the end destination don’t know if they will be caught out.”

Around 40 percent of the 300,000 tons of lamb produced in Britain annually is exported, of which 96 percent enters the EU — mainly France, Belgium, Germany, Spain and Italy.

“It’s a real muddle. There is a lot of work going on … But there is still no decision made and industry has been given no guidance on what to do. There has been a total lack of understanding,” Stocker said, adding that the government has also failed to clarify how it plans to attract seasonal contractors to work in the country’s abattoirs in the event of a no-deal. A huge proportion of abattoir staff currently come from Eastern Europe.

On Thursday, U.K. Farm Minister George Eustice said the government is exploring slashing tariffs on goods coming into the U.K. as a way of sheltering consumers from price hikes in the event of a no-deal Brexit.

But the Cabinet is divided on the tariffs issue, with Environment Secretary Michael Gove pushing for higher tariffs to protect British farmers, while Chancellor Philip Hammond and International Trade Secretary Liam Fox want lower duties to protect consumers from higher prices in the shops.

If there is no deal, the EU is likely to levy full external tariffs on food coming in from the U.K., meaning an increase of at least 40 percent on sheep meat and beef — with 100 percent tariffs on specific cuts. With the threat of EU tariffs imminent, Minette Batters, president of Britain’s National Farmers' Union, this week gave Secretary Gove a public dressing down at the NFU's annual conference — speaking of her dismay at the “insanity” of politicians.

A no-deal Brexit would require the government to put tariffs on sheep meat, beef, poultry, milk, cheese and pig meat in order to safeguard domestic production.

“Britain was ... assured that a trade deal would be the easiest deal in history, that Britain holds all the cards in the negotiations. Well, conference, in a few weeks' time if there isn’t a deal with the EU, high export tariffs could effectively mean we have no market for four and a half million lambs,” she told delegates as Gove looked on. “With 900 hours to go, it’s unacceptable for government to leave British businesses having to take this gamble.”

Gove conceded in his speech that a no-deal Brexit would require the government to put tariffs on sheep meat, beef, poultry, milk, cheese and pig meat in order to safeguard domestic production. He also underlined that all animal products entering the EU would face health and safety checks, resulting in delays in loading ferries in Calais.

U.K. exporters will also need to comply with new customs paperwork and a new labeling scheme will be required for products of animal origin exported to the EU. “I emphatically do not want to run the risks that leaving without a deal would involve,” Gove said.

But if no deal cannot be avoided, his department’s preparedness will come under intense scrutiny, Batters said.

“It’s often said that the first responsibility of government is to defend its people and that the second responsibility is to feed its people," she said "On March 29, you [Gove] will be the first secretary of state in over 40 years with the responsibility, the duty of ensuring Britain is fed."