The head teacher of a failing Cleethorpes school has resigned a month after it was put under special measures by Ofsted inspectors.
Sue Hutson has been head at Matthew Humberstone Church of England School for nearly 10 years.
She said she felt privileged to have been head teacher at the school but "the time was now right" to move on.
An interim head, Ian Cox, has been called in to take over until a permanent replacement is appointed.
North East Lincolnshire Council said Mr Cox had previously been called in to take on the role of head teacher at two schools facing "particularly challenging circumstances".
A spokesman for the authority said: "In this regard Mr Cox has an excellent track record of success.
"The governors of the school and Local Authority are confident that he will be able to work with the existing staff to ensure the continued good progress of all the pupils at the school."