Sainsbury's-Asda merger in jeopardypublished at 08:15 Greenwich Mean Time 20 February 2019
The UK's competition watchdog has said the proposed tie-up between Sainsbury's and Leeds-based Asda could push up prices and cut choice for customers.
The Competition and Markets Authority (CMA) said it was "likely to be difficult" for the chains to "address the concerns".
The CMA also said the merger could lead to a "poorer shopping experience".
Sainsbury's boss told the BBC the findings were "outrageous" and he would continue to challenge them.