Can anyone give me some advice?
The engine warning light has come on on my focus st 170, is it safe to drive at all? Any advice would be appreciated, Many thanks.

 

It could be a a multiple of things mate. I think i am right in saying If its a failed sensor or anything the ecu will use its memory from last known info to keep the car running as normal but illuminate the light. Always best to get it checked asap. Could be something minor or something major.
Better to be safe than sorry.

 

It's perfectly safe to drive,it's just it maybe down on performance etc as the ecu can go into "limp home" mode.
Don't be the least bit surprised if the light goes off after a few days as it can be triggered by virtually anything.
As said above,get it checked but don't panic about it!!!most places charge about £30 to check it,tell you the fault then switch it off.most usually waive the fee if you allow them to repair it as well.
Pointless speculating as it literally could be anything.