Glenn wales

Thanks magnet , what is the purpose of the switch on the clutch pedal ?

Need to change the brake light switch on my car but was just wondering the switch that sits beside it that connects to the clutch pedal is it imperative that  this is also working cos its pretty battered up for whatever reason will i need to renew that also ? Tbh im not really sure of its function so dont no if its working or not can anyone enlighten me 

As the title says whilst driving i get a sudden loss of power if i take my foot off the throttle and then back on the power returns , accelerates fine under load but at a steady speed the power will just drop out ive changed the fuel filter hoping it may have had a blockage but its still the same HELP