This weekend Glastonbury is celebrating its belated 50th birthday, and over the past five decades there are now several traditions that we can rely on each year. There will be a bit (or a lot) of rain, Paul McCartney, a lot of Hunter wellies and a sighting or two of Sienna Miller and Kate Moss. Today Sienna was photographed at the festival in two outfits which we think will go down in Glasto history. First she wore navy and deep red striped trousers, with a red pinstripe overcoat. It’s fabulously eccentric thanks to the clashing prints, and looks amazing against the tents and festival flags. But the outfit that has really caught our attention is her brown linen mini dress, which has spaghetti straps and an open criss-cross back.