Sainsbury’s has said the supply of some fish, dairy and meat products to its stores in Northern Ireland could be significantly reduced from January because of Brexit. Simon Roberts, the chief executive of the supermarket chain, said on Thursday: “If we don’t get greater clarity on the Northern Irish situation then we will see a restriction on the ranges of products we can sell. This is not one or two products in stores I am talking about, it is a substantial number of products and quite key, everyday products too.” Supermarkets’ supply chains will be hit by Brexit whether there is a free trade deal or not between the EU and the UK because the Northern Ireland protocol kicks in at 11pm on 31 December. Under the deal struck by the prime minister, Boris Johnson, fresh food coming into the region from Great Britain will be subjected to checks including customs declarations, and health certification protecting the island of Ireland from outbreaks of infections such as salmonella. Roberts said the industry was pushing for clarity as soon as possible on trading with Northern Ireland post-Brexit to prevent shortages in stores there from January. He said the industry had a “productive” meeting with government last week and wanted something akin to “trusted trader status” to help the flow of goods. “Customers expect to have access to a full range but [it] won’t be possible to make that available unless something changes,” Roberts said. Sainsbury’s has 13 stores in Northern Ireland, and its experience will be mirrored by its rivals Tesco, which has 55 stores in the region, and Asda, which has about 20 shops there. Both chains also source a lot of their products from mainland UK. Roberts said: “Customers are expecting value for money and continuity of supply. We need clarity from government to help us to be able to do that.” He said the problems could affect a “substantial number of products” including processed meat, such as mince and sausages, as well as fish and dairy items. Marks and Spencer said on Wednesday that its business in Ireland could be affected if no deal was agreed with the EU, and significant tariffs and bureaucratic costs were added to food imports – a development local business leaders have been warning about since January. It is understood supermarkets are also concerned that the EU has yet to grant a third-country listing, which would confirm that the UK conforms with EU regulations. While that listing is privately expected to be granted, the lack of clarity has put food suppliers, including Scottish seed potato companies, which sell into Northern Ireland, under “incredible strain”, according to Holyrood’s environment minister. With 55 days to go before the end of the transition period, there are many other outstanding issues affecting food suppliers in Great Britain, including the labelling and rules applying to food with ingredients from outside the EU. While significant differences remain in negotiations between the UK and EU, trade talks on Brexit are expected to continue from Sunday. If a deal can be struck it is expected that products that are more than 50% British will qualify under a rules of origin regime for tariff-free and quota-free sales across the EU. Under the Northern Ireland protocol, EU rules will apply in the region, so supermarket chains transporting food to shops in Belfast, Enniskillen or Derry will also have to satisfy rules of origin specifications. This requirement could affect the sale of biscuits, for example, if the grain has been sourced from Ukraine or elsewhere. Dominic Goudie, the head of international trade at the UK’s Food and Drink Federation, said: “Producers are now preparing for this worst-case scenario and many are planning to stop supplying the Northern Ireland market after 1 January 2021, to make as yet unconfirmed changes required for product labelling or while they assess if it remains a viable option for their business.”