I am currently leaving in UK. I want to know how can I apply for Portuguese passport from here.

If you are portuguese , and or/ both or any of your parents hold a portuguese passport/ nationality, it should be very simple, just go to the portuguese embassy/consulate and request it, make sure you have all the details , names, dates and birth places, and your wallet, but you have to be there on the qeues very early, if you're not there by & am, don't bother, because it does get very busy