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.
More top news
The victim, who was also 15, was stabbed repeatedly just yards from the Capital City Academy School in Willesden.
Crossrail contractors have been hit with a fine of more than a million pounds over the death of a worker and other incidents.
Anh Nhu Nguyen, 52, claimed he lived in the North Kensington block and that his wife and son had died in the fire.