I have a VW Polo (2006 Reg). This morning I set off from my house and after driving for about 2 minutes after I'd driven over a few road humps the car started screeching. At first I though it was the brakes as its been raining quite a lot and the cars been on the drive for a day without having been driven but the car was screeching without applying the brakes. I checked under the bonnet and under the car but couldn't see anything unusual. What I did notice was a white mayonnaise like material had built up under the driver side wheel arch. After I stopped and drove a little further the screeching eventually went away but the car definitely doesn't feel right.

Any ideas what this mayonnaise like material is under the driver side wheel arch - it's certainly not something I've driven through.

And what could have been the screeching noise.