The Competition and Markets Authority has provisionally decided that Aldi Stores Ltd, Lidl Great Britain Ltd and Lidl Northern Ireland Ltd should be treated as Large Grocery Retailers under the Groceries Market Investigation (Controlled Land) Order 2010, extending rules that already cover the UK's biggest supermarket chains. The order is intended to stop large grocers from using restrictive covenants and exclusivity arrangements in land agreements to make it harder for rival supermarkets to open nearby, with the aim of protecting competition, consumer choice and grocery pricing. The order currently applies to Asda, Co-op, Marks and Spencer, Morrisons, Sainsbury's, Tesco and Waitrose. The CMA's provisional view is that Aldi, Lidl GB and Lidl NI now meet the threshold because of the scale and geographic coverage of their stores, their full grocery offer and their procurement model. It said each operates grocery stores with a shopfloor area of more than 1,000 square metres across either Great Britain or Northern Ireland, each carries a full range of groceries despite offering less choice in some categories than some existing large grocery retailers, and each buys groceries directly from suppliers through an integrated grocery wholesaling function. When the order was introduced in 2010, Aldi and Lidl's UK activities were excluded as limited assortment discounters, a category used for chains selling a significantly narrower grocery range at low prices. After reviewing current evidence, the CMA provisionally found that Aldi, Lidl GB and Lidl NI no longer qualify for that exclusion. The regulator said the UK food and grocery market is worth an estimated 215 billion pounds and that various sources rank Aldi and Lidl among the top five retailers by market share. Juliette Enser, Executive Director of Competition Enforcement and Markets at the CMA, said: "We want everyone to have the best choice of supermarket and range of prices when buying their groceries. To ensure this happens, we put rules in place to prevent big supermarket chains blocking rival stores from opening nearby - and now we propose applying those rules to Aldi and Lidl too. This is about allowing shoppers to choose where they spend their money and levelling the playing field for all major supermarkets. Today's proposals are provisional and we welcome views before deciding the best way forward." No final decision has been made. The CMA is seeking views from stakeholders by 5pm on Monday 7 September 2026 and said it will consider responses before reaching final decisions in the autumn.