Harrison (pictured) will take responsibility for the field business development manager (BDM) team and will report to mortgage distribution director Brad Fordham.
She joined Banco Santander in 2007 and has been north regional manager for its intermediary mortgage operation since 2013.
In all Harrison has more than 20 years’ experience in the BDM arena, including positions at Northern Rock, Alliance and Leicester, and Santander.
Fordham said: “I am delighted that Helen has been appointed and have no doubt that she will bring real enthusiasm and new thinking to the role.
He added: “We wish Paul the very best in his new endeavours.”