We need some detailed pictures, Holly. Preferably of the top and bottom of the leaves.

Tell us more about how you've been growing it.

Is it indoors?

Hello, I thought the picture I used uploaded with my post. Sorry about that.

The plant is currently indoors, it was a gift and I wanted to keep it. I move house soon, so it will be going into the garden where it belongs, for now though, I just want to keep it as happy as possible in the conditions I have.

It gets around 5-6 hours of morning sun, on and off, its not direct. I have moved it away from the window, because I know it doesn't like too much sun, but that made it sad!

Since the picture though, I trimmed it down a bit. I have checked the plant, it currently still hasn't outgrown the pot it is in, so for the 30 days it has left inside, I wont repot it.

Being indoors is probably the main problem. Low light and lack of wind, rain and predators mean indoor herbs tend to get sickly. Im guessing you're in the UK? Mint is getting scrawny at this time of year anyway and will die down in the winter.

I see new growth at the base so I'd rinse the foliage under the tap, put it back in the lightest place you have and cross your fingers. Outdoors mint can take a little shade but inside is much darker already and it needs all the light you can give it.

Yes! I'm currently in central London, excited to move just to have more plants! Haha.

Thank you for that, I'm just glad I kept it alive this long indoors.

Somehow London would have been my guess from the brick wall outside. Seen a lot of flats with views like that!