Joanne McCartney
Following the election of Sadiq Khan as Mayor of London in 2016 , McCartney has served Statutory Deputy Mayor of London . 
<triplet> Sadiq Khan <subj> Mayor of London <obj> position held <triplet> Mayor of London <subj> Sadiq Khan <obj> officeholder <subj> Deputy Mayor of London <obj> substitute/deputy/replacement of office/officeholder