Rarely can a crit have witnessed such a poignant moment. The event was the aia annual design charrette (excellent as ever), taking place at Toynbee Hall in London's East End. The subject: accommodation for the homeless. The moment: in the middle of one student team's explanation of their proposal, pinned on the inside of an external door, a great knocking comes from the other side. The door is opened. A genuine homeless person staggers into the room, treads on the model, and slumps into a front row seat as guest critic Fred Koetter, without batting an eyelid, interrogates the designers about their scheme. A crit taking urban reality, literally, on board? It should happen more often.