Without knowing what engine type/code you have it could be one of a few things 

17 minutes ago, nige8021 said:

Without knowing what engine type/code you have it could be one of a few things 

Hi it’s a 18t petrol Skoda Octavia 

@Andyroberts I may not be looking at what you're meaning to point at but the whitish thing is a tie-wrap.

8 minutes ago, KenONeill said:

@Andyroberts I may not be looking at what you're meaning to point at but the whitish thing is a tie-wrap.

I know that’s a cable tie 🙄 I mean the thing that the cable tie is wrapped around

Your picture feels a little too zoomed in for me.  My best guess is this part...

 

42 - Solenoid valve for charge pressure control -N75- */**

 

Its a vacuum solenoid, normally housed in a piece of rubber to mount to something. Rubber has probably fallen away so someone has cable tied it in place.