Police officers fired an electric stun gun in their own black Race Relations Advisor's face after mistaking him for a wanted man, it emerged on Friday.

A passerby filmed the officers confronting 63-year-old Judah Adunbi - who works to smooth relations between police and the black community - and ask for his name.

But when the indignant grandfather refuses and tries to enter his home officers shout "Taser" and shoot the electric gun at his face.