[Insignia - what is this part?]

It keeps making like a short, loud humming noise, like it’s trying to apply the brakes or something? It only happens when you apply the handbrake but has started doing it repeatedly every few seconds. When you press on the foot brake  it stops. The noise is coming from this part and it vibrates quite severely when it does it. 

[Insignia - what is this part?]

Hi

i wondered if anyone could tell me which part this is? It’s at the front, just to the left hand side of the power steering fluid tank. Thanks.