Britain's regulator blocks the Sainsbury's Asda merger

Chris Ratcliffe | Bloomberg | Getty Images

A Sainsbury sign stands on top of a gas station canal, considering an Asda sign over the entrance to the Watford supermarket, UK, Monday, April 30, 2018. The UK's competition regulator has blocked Sainsbury's proposed 7 £ 3 billion ($ 9.4 billion) acquisition of Walmart-owned Asda – a major blow to the supermarket groups who wanted to combine to take over market leader Tesco.

The Competition Authority (CMA) said in its final report on Thursday that the agreement would lead to increased prices in stores, online and many gas stations across the UK

Sainsbury, Walmart and Asda said they had mutually agreed to terminate transaction.

Sainsbury and Asda agreed in April last year. In addition to taking over market leader Tesco, it would also have given Walmart a way to end the UK, one of the weakest players in its global portfolio.

However, in their final report, CMA found that British buyers and motorists would get worse if Sainsbury and Asda merged.

It concluded that the agreement would lead to a significant reduction in competition both at national and local level.

It said this would mean that buyers across the UK would be affected not only in the areas where Sainsbury and Asda store overlaps.

"We have concluded that there is no effective way to deal with our concerns, other than blocking the merger," said Stuart McIntosh, head of the CMA Request Group.