SmartCars have legitimised the idea of not parking parallel, but parking sideways to the road, driving in and out.
Now that it is legitimate, there's no reason why it should be restricted to smartcars. If everyone parked this way, the parking capacity of the cities streets would double.
Here, the Ford Focus D14TJD shows how it can be done, turning a narrow pedestrian crossing that was not big enough for a car, into a parking space. Being a small family car, the Focus barely protrudes out.
Vehicles approaching the junction from the other side, (Eaton Crescent Clifton) do see it, but by sharpening the junction they force these cars to give way properly, instead of pulling out at speed.