Ever since the Olsens sent models down the runway in long, side split tunics in their SS15 show for The Row, I have been obsessed with the things. This white one from Missguided has a slightly more accessible price point of £25 and works just as well. I'd wear it over culottes or wide leg trousers for the perfect spring/summer look. ASOS has a great offering too - find similar ones here, here and here.