The full message on the school's website from Dr J J Saxton, director of education at Future Academies, said:
I am writing to let you know that having successfully set up and opened Pimlico Primary, Annaliese Briggs has decided to leave Future Academies to pursue other opportunities within primary education.
A new principal of Pimlico Primary has been appointed. Coming from within the group, our new principal is already known to you and your children, and brings over 10 years experience in both early years and leadership.
We are delighted that Annaliese will continue to support Pimlico Primary as it grows by becoming a governor.
Annaliese Briggs used to work on education reform and the curriculum for the Civitas think tank, and studied English at Queen Mary, University of London. She was controversially appointed as head of the central London school in March.
It is believed that at the time she had no formal teaching qualifications, but spent time working in primary schools in Wandsworth
Pimlico Primary, which began admitting pupils for the first time last month, is sponsored by Future, a charity set up by Lord Nash - a minister in the Dept for Education
A headteacher appointed to run a free school despite having little experience or teaching qualifications has left the job just weeks after it opened. Annaliese Briggs is leaving "to pursue other opportunities within primary education", according to a notice to parents on Pimlico Primary's website.