It is going to be very interesting to watch the FA handle this situation. With Suarez and Terry, they let the affected parties be tried in the court of public opinion for months. After gauging which direction the wind is blowing, they acted and provided a sentence which was consistent with the public opinion.
This one appears to be more complex.
and Oh... When I said "It is going to be interesting, I meant it is going to be fun 🙂) "
This is the very essence of the FA's problem now. They've allowed themselves to be influenced by other parties with an agenda instead of actually looking at the situation and looking for actual proof.
They either side with Chelsea as 'surely they wouldn't complain without reason' and Clattenburg's dead or they refuse to believe the allegation and Chelsea have to be sanctioned for false allegations and Clattenburg's still tainted.
Ferguson and Wenger's intervention has now ratcheted up the pressure, if they clear Clattenburg many will say the FA have been influenced.
They've got themselves in a mess, the current 'guess the probability' test they apply isn't rigorous enough.