Some news of earth-shattering proportions hit the Newton household this week.

A new study led by the University of Plymouth suggests that some teabags manufactured using plastic alternatives are not as biodegradable as you might assume, and have the potential to harm terrestrial species.

The research was designed to replicate the environmental conditions into which teabags might reasonably be discarded if clear instructions were not provided – for example, a food waste caddy or a garden compost bin.

The trial focused on commonly available teabags made using different compositions of polylactic acid (PLA), which is derived from sources such as corn starch or sugar cane.

These were buried in soil for seven months, then assessed as to what extent they had changed both visibly and structurally, using a dazzling array of analytical techniques from size exclusion chromatography to nuclear magnetic resonance and scanning electron microscopy.

Alarmingly for ecologically-minded cuppa suppers, teabags made solely from PLA remained completely intact. However, the two types of teabags made from a combination of cellulose and PLA broke down into smaller pieces, losing between 60% and 80% of their overall mass with only the PLA component remaining.

Only one manufacturer chosen for the study indicated on the packaging that the teabags were not home compostable. Consumer confusion was also identified around the meaning of terms such as plant-based or biodegradable.

Here at Newton Towers, tea-making methods are under constant scrutiny. The Other Half insists on tea leaves, not because he’s a tea snob but because “bags are bad”.

The trouble is, of an evening he only wants a small cup of tea (being a man of a certain age, he doesn’t want to wake up in need of a night-time tinkle).

And he does so like me to make it for him. It appears to have become an enduring symbol of my affection, especially when served with a snack (cheese and biscuits being a particular favourite).

But if only large mugs are left, I must only half-fill it. This means the tea strainer isn’t close enough to the boiling water to steep, resulting in a dishwater brew and a pout from my partner.

“Would you like me to show you how to make a proper cup of tea?” he has asked me, more than once. I’ll leave you to imagine my response – it’s along the lines of “if you don’t like the way I make it, you can always make it yourself,” but with a few (OK, a lot of) expletives thrown in for added emphasis.

When I do the food shop and tea is on the list, I dance a little jig in the supermarket aisle when the loose-leaf tea has sold out. I don’t have a death wish for the planet, but it’s just so much easier to make a cup of char for a fussy person with a bag.

So I was gutted to see that even the environmentally friendly bags don’t quite hit the mark. Apparently, the humble earthworm, so important for soil health, is 15% more likely to die if it ingests PLA teabags, and could also find its reproduction compromised.

So there you have it. We are murdering worms and their future babies when we use a teabag.

The study’s authors have highlighted the need for accurate disposal information to be clearly displayed on product packaging – essentially, put it in the bin and divert it to landfill, which is rather defeating the object. 

Better still, buy loose-leaf. I do so hate it when OH is right, and it’s not as if it’s news. I use those “compostable” bags in my food waste caddy, and transfer them to our garden compost bins; they are still there weeks later, when the next one goes in.

Similarly, previous research suggests that carrier bags and other products labelled as biodegradable are still intact after as much as three years in the environment.

It suggests that biodegradable plastics, which are being used in an increasing range of products, are really storing up a generation of alternative problems if they are not properly understood or disposed of.

It’s rather like inventing vapes to wean people off smoking, only to discover that people who have never smoked are now addicted to pastel-coloured, fruit-flavoured nicotine.

Of course, there are solutions. A reusable shopping bag, for example (I once read about an old lady who had 1,000 bags for life – who lives that long?)

And as for the first-world problem of OH’s herbal nightcap, I could use a small cup, or a ball-infuser (OH bought me one for my own fancy teas, drunk without milk, and I can attest that it’s very effective).

Or maybe – whisper it – OH could switch to bedtime tea-making duties. Perhaps I could warm his slippers instead…