Sir Victor joined the Mirror Group as chairman in 1998 and oversaw the merger between Mirror Group and Trinity a year later.
As well as a number of non-executive roles, he is chairman of the retail conglomerate GUS plc, and there is speculation that he will take on the additional role of chairman of Lloyds TSB later this year.
Speaking about the announcement, Blank said: "Media and newspaper publishing is a fascinating and challenging industry.
"Our newspapers are part of our heritage and the opportunities presented by emerging technologies are enormous"
He added: "The management team I leave behind are first rate and fully focused on the delivery of the options for growth."
Sly Bailey, chief executive of Trinity Mirror described Sir Victor as "outstanding".
He said: "Victor's wealth of experience and deep understanding of the challenges faced by public companies has been of immeasurable help to me and the management team."