Mystery surrounds the absence at John Bentley School in Calne of headteacher Laura Carleton after an investigation into her was launched by its governors.

The investigation comes at the same time as the Crown Prosecution Service announced no further action would be taken against the head of Calne’s Springfield Academy Trystan Williams, who was suspended from the award-winning specialist school in October last year while police investigated a report of an alleged assault on a pupil.

John Bentley governors said in a statement on Tuesday that Ms Carleton would not be at the school for the foreseeable future pending an investigation by governors. Melanie Sutton, a member of the senior leadership team, will be acting principal.

A letter was sent home to parents on Tuesday.

Parent Tracey Pike, said: “A better explanation would have been appreciated but I obviously understand it is early days and hope more information will become available to us concerned parents and carers.”

Ms Carleton joined John Bentley in September 2013. She was previously deputy head of Bristol Grammar School.

Meanwhile police said Springfields principal Mr Williams’ bail has been cancelled.

A spokesman said: “We can confirm that after completing a thorough and complex investigation the bail of a 43-year-old Calne man arrested following an incident where a child was seriously injured at Springfield Academy in the town has been cancelled.

“Whilst we appreciate this case has been prolonged, due to the nature and scope of the investigation, it is absolutely right that all necessary enquiries were comprehensive and thorough, as the public would expect.

“We have worked closely with the school, the local authority and appropriate partner agencies throughout. This is now a matter for the relevant agencies to progress with Springfield Academy.”

A Crown Prosecution Service spokesman said: “The CPS was asked to consider whether there should be prosecutions in relation to incidents that occurred at Springfield Academy in 2013.

“Two files of evidence were submitted by Wiltshire Police. One in relation to an alleged assault by a 43-year-old man, and another one in relation to an offence of attempting to pervert the course of public justice by the same male and another 43-year-old man.

“Following a careful review of all the evidence available and in accordance with the Code for Crown Prosecutors, the decision was made that there was insufficient evidence to provide a realistic prosecution in both cases and therefore no charges should be brought against any individuals.”

Springfield Academy would not comment.