The skirt shape of the season is the dirndl. But what is it? Its below-the-knee, full and flirty with a circular cut. Everyone from Dries Van Noten to Jil Sander sent them down the catwalk, but the must-buy of the summer is by print-master Jonathan Saunders. Grown-up, playful, prim, sexy, retro-modern... and whats more, its a skirt you can throw on with flats, smarten up with a wedge, wear with a shirt in the office, or a simple vest for summer. Heres the six best