The two high street giants are in “advanced talks” to create a combined business which would become Britain’s biggest supermarket group.
Details of the £10billion deal are set to be announced today. But fears were raised yesterday over consumer choice and the impact it may have on jobs.
Liberal Democrat leader Sir Vince Cable said the Competition and Markets Authority (CMA) “must investigate” any deal.
Shadow business secretary Rebecca Long-Bailey warned the merger risks “squeezing what little competition there is in the groceries market even further”.
Sir Vince said the CMA should force the companies to sell off stores if the merger meant the new giant was dominant in a particular area.
He told the watchdog’s new chief, Andrew Tyrie, to “get tough with monopolies”.
Ms Long-Bailey warned that, in the absence of proper vetting, it would be “British shoppers that suffer from rising prices and British workers that may be fearing for their jobs”.
Sainsbury’s has a 13.8 per cent grocery market share, Asda has 12.9 per cent.