I’ll try to explain biba70.
Often, foreign-made products are cheaper to buy wholesale than British-made ones. Any seller, therefore, makes less profit on a British product than on a foreign one. Most buyers don’t care where the thing comes from, they just want a reasonable price.
Chain stores can buy things for less money by buying in bulk, and can afford to sell individual items with only a small profit because they can expect to shift large numbers.
Individual local shops buy goods in smaller quantities than chain stores, so the cost per item is higher. In order to make enough profit to stay in business, many choose to buy cheaper, foreign made items and sell them for a higher profit.
You may be prepared to shop around and pay more for a British made jar, but most people just want a cheap jar that does the job, and shops have to provide what customers want.
So your local shop may be selling Chinese-made jars for the same price as a chain store British jar. If you buy à British jar from the chain store, you help to pay the shareholders’ bonuses. If you buy a Chinese jar from your local shop, you keep one of your neighbours in business.
Does that clarify?