Sainsbury’s proposed merger with Walmart-owned Asda is full of big numbers – and big numbers when it comes to sales and profits are the objective.

The enlarged business, assuming the competition regulators allow the deal to go through, will have combined sales of £51bn, generate net EBITDA synergies of at least £500m, and a total of 2,800 stores will handle 47 million shopper transactions per week.

It’s a deal that could transform the retail landscape – both grocers are also big powers in clothing and general merchandise – and “substantial value creation” is promised for shareholders.

“The merged business will stand or fall upon something far more difficult to map out – whether the people involved will get along, and a shared business culture”

But whether or not the ambitions of the merger are realised will depend not solely upon the excellence of strategy nor how the maths works out on paper.

The merged business will stand or fall upon something that is far more difficult to map out – whether the people involved will get along, and a shared business culture.

Such considerations can appear touchy-feely in comparison to the hard work of successfully executing a deal and delivering the results, but you only need recall the underperformance that followed Morrisons’ and Safeway’s tie-up in 2004 as a brutal reminder of what happens when there’s a clash, rather than a marriage, of styles.

“This isn’t a merger, it’s a takeover,” Sir Ken Morrison famously proclaimed to Safeway staff, coming across as a conqueror rather than an ally.

Unsurprisingly, his domineering approach resulted in alienation and resentment at Safeway – and contributed to Morrisons reporting its first-ever loss just a couple of years later.

This time around, the omens look much better. As well as the Sainsbury’s big guns – chief executive Mike Coupe and finance boss Kevin O’Byrne – Walmart International chief executive Judith McKenna and Asda boss Roger Burnley were on hand to emphasise how the companies, each of which will retain its own fascia and head office, will work in partnership.

“Mergers work not because of what the agreement says, but because of the people and the culture in the two businesses,” McKenna maintained. “Our hearts and minds align.”

Spirit of co-operation

A common approach should be helped by the fact that Coupe is a former Asda trading director, while Burnley joined the Leeds giant directly from Sainsbury’s.

That spirit of co-operation rather than one-upmanship must be fostered among the 330,000 staff across the two businesses – which, of course, must in the meantime remain deadly rivals competing against each other until the deal completes in the second half of next year.

McKenna summed up the ambition nicely when she said she hoped it would allow Asda and Sainsbury’s each to become “better versions of themselves” as best practice is shared, differences complement one another and synergies are created.

If that is successfully done, then perhaps the merged company will realise the “transformational opportunity”, in Coupe’s words, “to create a new force in UK retail, which will be more competitive and give customers more of what they want now and in the future”.

And if it does, it will be better positioned to fend off Amazon if, as UK grocery consolidates, the Seattle Goliath decides to make a play for a big British grocer.