Most tea bags contain plastic. The plastic in tea bags is used to seal the bags and / or to stop the bags from tearing.
I don't want to be drinking plastic micro-particles. Nor do I want to add plastic fragments to the soil in my garden when making compost. I certainly don't want badly-disposed-of tea bags to be lingering in the environment for hundreds of years and/or choking wildlife. Oh dear.
Some (rather expensive) brands are already plastic free and now, luckily, the day-to-day brands are following suit, such as PG Tips, TickTockTea and Clipper. If you drink herbal tea then it's useful to know that Pukka tea bags are plastic-free.
If research shows that your tea bags contain plastic then don't put them into a garden compost bin, or the micro-particles of plastic will end up in your garden soil. Oh dear.
You could of course choose to use 'loose' tea, but make sure that the infusing kit you choose has really tiny holes (so there's no tea 'dust' in your cuppa) and that it is easily cleaned. The stainless steel insert from the Chiswick Tea Company sits inside your cup, has very fine holes and comes with a drip tray. Or to fit any size mug / cup, try the tea infuser from Peace With The Wild (sent out in plastic free packaging). I use reusable cotton teabags - similar are available from Eco Living (again sent out without plastic packaging).
Wait. There's more. The BBC's 'War on Plastic - The Fight Goes On' TV show highlights that big name cafe chains are still using plastic-containing tea bags. Oh dear. So let's all start asking cafes to stock plastic free tea, once their current stock of tea bags has been used up. Everyone can do their bit towards making a difference.