The offside front strut spring had failed and dug into the front tyre!!!
I've not heard of this happening before and if it had happened last night as I was driving home at speed in traffic I really wouldn't have rated my chances....
If you look at the first photo:
Pic of the spring
You can see that it has failed just at the point where the lower cup drops down.
In the 10 yards or so that I slowly drove it, here is what it did to my lovely new Toyo Proxes T1-R....
Pic of the tyre
I really feel quite lucky to be alive....
Has anyone heard of this happening before??
Ron