The proposed merger between Sainsbury’s and Asda has been blocked outright by the Competitions and Markets Authority (CMA).

The CMA’s judgement concludes the deal would be bad news for consumers.

Stuart McIntosh, chair of the inquiry group, said: “It’s our responsibility to protect the millions of people who shop at Sainsbury’s and Asda every week. Following our in-depth investigation, we have found this deal would lead to increased prices, reduced quality and choice of products, or a poorer shopping experience for all of their UK shoppers.

“We have concluded that there is no effective way of addressing our concerns, other than to block the merger.”

Sainsbury’s Mike Coupe, reacting to the news told the BBC: “The CMA’s conclusion that we would increase prices post-merger ignores the dynamic and highly competitive nature of the UK grocery market.”

The former Asda executive, Julia McKenna, now head of the international division at Walmart said: “While we’re disappointed by the CMA’s final report and conclusions, our focus now is continuing to position Asda as a strong UK retailer delivering for customers. Walmart will ensure Asda has the resources it needs to achieve that.”

The CMA’s investigation found that, as well as affecting in-store customers, the merger would result in increased prices and reduced quality of service, such as fewer delivery options, when shopping online.

In making the decision to prohibit the merger, the Group reviewed a wide range of issues in detail, such as the increased competition presented by discount stores like Lidl and Aldi, and how new or expanding competitors could affect the retail market, including online.

Whilst the panel carefully considered these industry developments, they did not allay its serious competition concerns about the merger.