Mystery butterfly

I have several ‘butterfly friendly’ plants in my garden but I only ever see boring white butterflies.

Today at Heligan I saw this one! I’ve done an online search but can’t find out what it’s called. If anyone knows I’d appreciate being told what it is!

The weather forecasters got today right for once! A lot of rain in the morning and then a sunny/cloudy afternoon. I don’t remember wind being mentioned, but it was quite windy. I’m amazed that some holidaymakers were still dressed for the very hot weather we had last week - sleeveless tops and shorts! It was ALMOST cold in the strong wind so I don’t know how they coped.