If she's Scottish, why does she have an English accent?

In an interview she said it was because she doesn't most of her schooling years in England, I think it was London.

Sorry, she did her post secondary schooling in London, the other was in Sommerset.

As she said several times she has lost her Scottish accent living in France and then England since her ten years. There is no shame at all. The contrary, she always said that she is proud to be Scottish.

Lots of upper class Scots send their kids to English boarding schools and many of them pick up the accent. It's not uncommon. You can usually tell that there's a bit of something else there underneath, when you meet someone who's had their native accent squeezed out of them in that way but I guess with actors it's actually really handy, as it probably helps prime them for picking up accents when they need to professionally.

it depends on how drunk she is?