Turntables

[silverfoxcc]

Waay back in 1964 when i worked in 'The City'. just officework, nothing big!!, there were a lot of old roads that were cul de sacs and just wide ehougn for a car to get down. At the bottom was a circle wide enough for a cab ( horse type) to turn. In some of these they had installed a large metal turntable that would turn a car around. some of the more adventerous drivers would drive onto it ,hit the brakes, and let the cars momentum make the turntable spin round.
With all the building that has gone on sine then, the question is

Do any of these still exist, and work either in London or elsewhere?
pics would be nice