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.