Hi everyone, i have just bought a 2009 plate focus st, on the engine there is a pipe coming from the cowling below the windscreen which has been taped up and blocked at the end and im guessing where it should connect to it has been replaced with a bit of silicone hose and clamped off at that end. Could anyone help me by telling me what pipe should go here? I have circled the parts on the photo, Thanks in advance. 

It’s the sound symposer pipe. It’s to allow more of the induction noise in to the cabin. Some people don’t like it and block it off. 

As said above it's to allow more engine noise in the cabin. They're prone to boost leaks so people cap them off instead of fixing the leak.

Can also be removed if the car has had an atmospheric dump valve fitted in the past. The original setup uses a vibrating diaphragm to generate extra induction noise that’s then piped into the cabin. 

Aftermarket dump valves connect to the same outlet off the induction ‘Y’ pipe to bleed off intake pressure before the throttle body.

I removed and blanked off mine a few months ago after having the fight to remove it several times while going through alternator woes - with induction kit and aftermarket exhaust the extra intake noise is pretty much masked and engine bay looks a a bit tidier too.

Thanks for the replies, i had thought it was something ro do with the symposer but thought i would check, the replies are much appreciated, thanks.