On-off knocking noise from front suspension?

2005 Ford Fiesta 1.25 Zetec 5 door. Car was fine yesterday. Today my wife had trouble moving the car. When she did she only drove it for 100 yards max because of the terrible on-off knocking noise coming from the front of the car, she said it also felt like the car was sitting down at the off-side front, but no puncture. After driving it she also said there was a terrible 'hot smell' if that makes any sense. Any ideas ?

Iain
May 2008