The Competition and Markets Authority decided that Aldi, Lidl GB and Lidl NI would be designated as "Large Grocery Retailers" under the Groceries Market Investigation (Controlled Land) Order 2010, according to the report published on 22 October 2026. The order has applied since 2010 to Asda, Co-op, Marks and Spencer, Morrisons, Sainsbury's, Tesco and Waitrose.

The order is intended to stop large grocery retailers from using land agreements, including restrictive covenants and exclusivity arrangements, to make it harder for rival supermarkets to open nearby. Once designated, a retailer cannot include prohibited restrictions in new agreements, and existing agreements can be reviewed by the CMA at the request of interested landowners, developers and rival supermarkets. The CMA said it sought views in August and that Morrisons, Waitrose and Iceland responded in support of the proposal, while it received no representations from Aldi, Lidl GB or Lidl NI.

Juliette Enser, the CMA's Executive Director for Competition Enforcement and Markets, said the rules were put in place to stop big supermarket chains blocking rival stores from opening in their area. The CMA estimated the UK food and grocery market at £222.7 billion, with Aldi and Lidl among the top five retailers by market share.