These are life size pterosaurs, flying monsters the size of Spitfires, and there are currently three of them suspended above the South Bank complex. Two more are on the ground, nurturing their eggs and eating small dinosaurs.
It is quite a display and they are as realistic as possible, courtesy of the University of Portsmouth. Worth checking out but hurry as they will be flying away after tomorrow evening.
South Bank site here, BBC short film of their installation here and Wikipedia article here.