Thunderpants (fun cotton undies for all sizes)

Thunderpants is a slightly bonkers company (for people who love bright patterned undies!) that offers UK-stitched and finished undies, made locally to cut transport miles and support local economies.

The wide waistbands and flat seams prevent digging or chafing, and they hold up after each wash. You’ll also find matching vests and leggings.

Unless you’re going commando (!), you’ll be wearing underwear. Alas nearly all undies sold in England contain synthetic fibres (even ‘organic cotton’ ones tend to have 5% elastane for stretch).

So, unless you wear 100 percent organic cotton briefs, wash them with a microfiber filter, because it helps keep microplastics from washing out of machines and into the sea.

Synthetic fibres (nylon, polyester) are made from oil. So by choosing brands that are mostly made from cotton, it’s help to avoid supporting the oil industry, which causes pollution and climate change.

Charity shops won’t take used underwear, mainly for hygiene reasons. However, you can still drop old pairs, even torn or worn, into a textile banks. From there, the fabric gets shredded and turned into industrial products.

When buying new undies, measure your waist and fullest part of your hips, to avoid sizes that are too tight and cause chafing (or unflattering bulges!) Avoid irritating tags, and choose nude tones, to prevent ‘visible panty lines’.

To make undies last longer, launder with unscented biodegradable laundry detergent and avoid fabric softener (reduces absorbency) and tumble driers. For stains, use natural oxygen bleach.

Don’t believe the greenwash about M & S undies being the best. Most are made from cheap polyester, meaning they don’t let your skin breathe, and are very expensive for the material used. You’re better off shopping around at budget clothing stores, to find ones made with cotton.