MarmiteTesco and Unilever are having a bit of a barney. At the heart of their disagreement is the pound note.

They say you either love or hate marmite, the same applies to the new, cheap pound. If you are an exporter, or if you are a multinational that enjoys much of its revenue in foreign earnings, you love it. If you are in the business of selling to the Great British public, you may hate it.

Unilever and Tesco have two things in common.

The first thing they have in common is that they sell to the Great British public.

The second thing they have in common is Dave Lewis. The man is now Tesco’s CEO, but for many years he was a star at Unilever – where he gained his reputation for being able to cut costs.

Actually, there is a third thing they have in common – they both love Marmite, but only because of the money it brings in.

Marmite, along with Surf, and Ben and Jerry’s and Persil, and PG Tips and many more products are supplied by Unilever.

Tesco, along with its retail rivals, sells them. And it wants to carry on selling these products cheaply. Unilever wants more money for them. And so the shelves are bare – or at least they are set to be absent of Unilever products.

The giant supermarket has had its problems of late, its golden age turned to a kind of iron pyrites age – fool’s gold. Accountancy scandals, falling sales, a disaster in the US: It took Dave Lewis to turn it around, and he applied a very simple formulae – focus on the UK business and respond to the challenge posed by the likes of Aldi and Lidl.

Tesco worked with suppliers – or maybe it cajoled suppliers – and got prices down. It paid off; in the latest quarter sales were up, profits jumped 38 per cent and it began to look as if the company had turned a corner.

Alas, the other side of the corner revealed a market in an era of the post-Brexit vote. And a much cheaper pound.

What people overlook when talking about the pound and the UK economy is time. Don’t forget sterling also crashed in 2008, but inflation didn’t peak until 2011. It will be several years before the effect of recent falls in sterling is fully reflected in prices.

When you try a bit of marmite, there is no delay, the taste hits you and you either say yum or yuk.

But with Brexit, the yummy effect, that is a cheaper pound helping exporters will take time, so will be the yukky effect – which is to say the hit on households’ affordability.

But the spat between Tesco and Unilever is a forerunner of problems to come. Tesco just wants to carry on applying its new found strategy of driving down price; Unilever is saying “err, excuse me, you do know the falling pound has hit our costs, don’t you?”

Expect such conflicts to occur more and more often.

But the in the long run, as far as retail land and its suppliers are concerned, the recent falls in sterling will leave a nasty taste.