Sandy Nairne, the current director of the National Portrait Gallery is leaving the job early next year in order to pursue his writing and arts work, The Guardian reports. Nairne has been director for the past 12 years, after he left his position at the Tate in 2002. Over the course of his leadership, visitor numbers have increased by a third to around two million a year and he has brought in sell-out exhibitions, such as the Freud exhibition which included the artist’s last painting left unfinished on the easel.

Nairne told The Guardian, “I am very proud of what we have achieved over the past decade. The fact that two million visitors now come each year to visit exhibitions, take part in activities or see displays of this amazing collection in London, as well as around the country or online, is testimony to the dedication of all who work at the gallery and those who support it in so many different ways. The gallery is in very good shape and will go from strength to strength.”

Nairne’s decision to step down has been followed by praise for his “exemplary” term at the National Portrait Gallery. Sir William Proby, the chair of trustees, comments on Nairne’s achievements: “He has significantly increased visitor numbers, put on some wonderful exhibitions, such asLucian Freud Portraits, and overseen many major commissions and acquisitions, including the [Anthony] Van Dyck self-portrait this year. He has built a very strong team and prepared them well for the future.”