Fiona Reynolds has announced that she is leaving the National Trust after 11 years as director general to take up the role of master of Emmanuel College at the University of Cambridge.

She will take up her new duties in September 2013, and will stay at the National Trust until a successor is in place. She also plans to write a book about her experiences at the charity.

“As a graduate of Cambridge I am thrilled to be going back to head one of its finest colleges,” Reynolds said. “I have loved every minute leading the National Trust and working with our passionate and dedicated staff, volunteers and supporters.

"There is no organisation like it and I will miss it terribly. But it is time to allow someone else an opportunity to make their mark.”

As director general of the National Trust, Reynolds has overseen a restructure of the governance of the charity from a 52-member council to a 12-member board of trustees, as well as two major internal restructures.

Under her leadership, membership has risen from 2.7 million in 2001 to four million last year. Visitor numbers have increased to 19 million from 10 million a decade earlier, while the number of volunteers has doubled to 62,000.    

Property acquisitions have included the Victorian gothic Tyntesfield and its estate near Bristol; Vanbrugh’s Seaton Delaval Hall in Northumberland; the ‘back-to-back’ terraced houses in Birmingham; John Lennon’s boyhood home in Liverpool; and the home of Kenyan-born poet Khadambi Asalache in Wandsworth, London.  

Simon Jenkins, chairman of the National Trust, said: “Fiona has presided over a triumphant era in the history of the National Trust. Her strategic vision and personal leadership have made it one of Britain’s most popular institutions.”

Reynolds is the first woman ever to be elected master of Emmanuel College.