Lettings agency Folio London staff members spotted the frightened puss clinging to the elevated section of the busy road after she was unable to escape from the traffic rushing past.
Leon Gaskin, Sara Persad and Breda O'Mahony rushed to the cat's aid - armed with just a towel and a cardboard box - driving to the bridge and pulling over amongst the busy traffic to grab her.
The rescuers believe she may have been deliberately thrown onto the dual carriageway from a car.
Leon said: "When we saw the cat in such a dangerous situation we knew she needed to be rescued quickly before she fell or was hit by a car.
"We were worried we might scare her when we got up there but luckily she was happy to come with us.
"We don’t know how she would have got up there on her own, so perhaps someone put her there."
The kind-hearted trio managed to get the cat - now named Bridget - into the box and took her to the Blue Cross hospital in Victoria.
Bridget received treatment for a grazed and bloodied chin but will be discharged soon.
Chief vet Mark Bossley said: "Bridget is very lucky to have been spotted in time. It could have been so much worse.
"Bridget is a friendly and trusting little cat, who thankfully has survived her terrifying ordeal pretty much unscathed."