Brown had been heading Citigate's Sydney affiliate CPR Communications & PR but returned to the UK for family reasons, and has joined Square Mile's financial services team under MD Ian Bailey.
Earlier this year, Square Mile hired Alex Clelland, senior director of corporate comms at international credit-rating firm Fitch Ratings - boosting the financial services team to 16.
‘Few industries have a PR task as complex or as involved as the financial services sector,' said WS UK & Ireland CEO Colin Byrne.