Police inquiries into the incident are continuing.
The attack prompted London Mayor Boris Johnson to call for London's borough leaders to do more about urban foxes.
"They may appear cuddly and romantic but foxes are also a pest and a menace, particularly in our cities," he told media.
"This sort of attack, though terrible, is rare, but we must do more to tackle the growing problem of urban foxes."
An RSPCA spokeswoman told BBC News it was unusual for foxes to attack people.
"It's not typical fox behaviour at all. Foxes will come closer to a house if there are food sources. Then they can become quite bold, but they usually do back off and run away when there's people around."
- nzherald.co.nz