THE competition watchdog will take into account the rapid growth of Aldi and Lidl when deciding whether to approve the £12 billion mega-merger between Sainsbury’s and Asda.

It was feared last month that Aldi and Lidl would not be considered in the Competition and Market Authority’s (CMA) investigation into the deal, after an initial analysis excluded the discounter chains as well as convenience stores.

But its latest update, the CMA said it has broadened its scope to include the German discounters as well as non-grocery competitors such as B&M, Amazon, and John Lewis & Partners.

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The CMA will now assess which other businesses can be considered competitors to Sainsbury’s and Asda.

Provisional findings will be presented early next year, while a final decision must be made by March 5, 2019.

Stuart McIntosh, chairman of the CMA’s inquiry group, said: “Millions of people shop at Asda and Sainsbury’s every week, so it is essential we carry out a thorough investigation into their proposed merger.

“Our job is to find out whether the merger will result in people paying more or being faced with less choice or a poorer quality shopping experience.

In their own submission to the CMA, Sainsbury’s and Asda said that Aldi and Lidl “have had the most profound impact” on the grocery market over the past decade.

The duo also pointed to the launch of Jack’s, Tesco’s new convenience store outlet.

The firms also described their marriage as “pro-competitive”, arguing that it will help enable

them respond better to changed consumer behaviour.

The CMA’s investigation will also consider whether the tie-up could lead to less choice, higher prices or poorer quality services.

It will look at whether the merged company could use its increased buying power to squeeze suppliers and whether this could have potential knock-on effects for shoppers.

Sainsbury’s and Asda have gone on record saying that suppliers will bear the brunt of a pledge to bring down the price of everyday products following their union.

It is also expected that scores of stores will have to be offloaded as part of the competition review.