a) Out shopping, in b) a skirt from Mulberry, working the "schoolgirl gone beatnik" look.
She also paid a private visit to an art therapy charity at a school in London - she's been making these secret visits as she decides which charities she'll use her royal weight to support - wearing a sweater and jeans, which apparently disappointed the kids who felt she "didn't look like a princess". (I hear ya, kids. I'd demand a tiara, myself.) Sounds like a basic miscommunication to me - she must have thought she was just going to slip in and out relatively unnoticed, while the school lined all the kids up like it was a legit royal visit. A simple mistake, and yet something tells me that's the last we'll hear of her trying the dressed down approach!