I'm a volunteer delivery driver for FareShare. FareShare is a registered charity which coordinates the collection of food and other items from supermarkets, wholesalers, logistics companies, and distribution to food banks, churches, schools and other charities.
One of the things we do is collect the items donated into the Tesco donation boxes. Besides the items donated by generous customers, the store uses the boxes as an efficient way of getting items to FareShare which are nearing their 'use by' or 'best before' dates. We weigh all collections and notify the stores, and they are able to display a thank-you message with this information on the boxes usually stating how many meals have been donated at a particular location in the last month.
What annoys me is not the boxes but the thankfully few members of the public who use the boxes as a dumping ground for out-of-date produce when they clear out their cupboards. Last week at one store there was an item donated with 'use by' date of 2021. This just wastes everybody's time. Why they don't just put stuff like that into the normal recycling/waste collection service I have no idea.
The donations add up, and some of the bigger stores in wealthy areas contribute a lot of stuff, by far the biggest source of donations is direct from the supermarkets themselves to the FareShare depots. I would estimate we get 60-70 percent of our donations directly from the supermarkets we work closely with, Tesco, Morrisons, Sainsburys and Marks and Spencer. The public doesn't see this side of it.
As others have said, none of this should be necessary in an ideal world, but the food distribution model in the UK is fundamentally broken. Efforts by organisations like FareShare are a sticking plaster over the cracks, but from what I see of our end customers, the need is real and growing.