A Poole primary school head teacher has been banned from the classroom after altering pupils' exam papers.
Maurice O'Brien, 60, who had been a teacher for 38 years, was found guilty of unacceptable professional conduct by a teaching regulator.
Mr O'Brien was banned indefinitely from the classroom after changing the test papers of 11-year-olds at St Mary's Roman Catholic Primary School, in Poole last year - causing their results to be annulled.
He told the investigators that a high staff turnover at the school had left him worried about pupils performance, and he changed the papers of the pupils "least likely to do as well as they should."
A professional conduct panel of the National College for Teaching and Leadership said Mr O'Brien had changed national SATs tests in literacy and numeracy in order to improve the results of "those least likely to do as well as they should".
"Those scripts raised suspicions by those examining them at the Standards and Testing Agency that they had been altered," the panel said.
"The STA notified the local authority on June 17, 2013. The local authority carried out an information-gathering exercise.
"On July 5, Mr O'Brien stated that it was he who had tampered with the papers. Mr O'Brien resigned from his post on October 6 and the matter was referred by the school to the National College for Teaching and Leadership."
The Coventry hearing heard that Mr O'Brien had admitted the facts of the allegations and also accepted that his actions constituted unacceptable professional conduct and that he may have brought the profession into disrepute.
He also acknowledged altering 30 out of 51 reading test scripts and told education officials: "It was me who tampered with the papers."
The panel noted: "The senior adviser for school improvement visited Mr O'Brien and the note of a subsequent interview with her states that Mr O'Brien had said that he was sorry, he had been weak and he apologised for his actions.
"It is stated in the interview note that Mr O'Brien was then asked to clarify what he was saying which was that he had altered SATs answer papers but that he couldn't remember how many.
"The panel also noted that in the notes of an interview carried out by an independent investigator with Mr O'Brien it is stated that Mr O'Brien readily acknowledged what he had done.
"That note describes how Mr O'Brien had access to the unsealed test papers, and that he altered some of them, focusing on those least likely to do as well as they should."
They said that in doing so, he was acting dishonestly.
"Mr O'Brien may have been motivated by a wish to prevent those pupils who may have underperformed from being personally affected if they thought they had failed," the panel said.
"Nevertheless, he would have known that he was acting in a way which ordinary people would have considered dishonest.
"The panel considered that Mr O'Brien may have acted in an impulsive way, but acted deliberately given that he stated that he 'focused on those less likely to do as well as they should'.
"The panel is satisfied that the conduct of Mr O'Brien fell significantly short of the standards expected of the profession.
"Mr O'Brien, an experienced professional and head teacher, abused the position of trust placed in him which resulted in the pupils' test results being annulled.
"The panel has taken account of the uniquely influential role that teachers can hold in pupils' lives and that pupils must be able to view teachers as role models in the way they behave.
"Mr O'Brien's actions served as a poor example to pupils who should understand that cheating is wrong."
Mr O'Brien, who did not attend the panel meeting, resigned in October last year after 17 years as head of the school.
The hearing heard that the school, which had received favourable Ofsted inspections in 2005 and 2009, had been suffering from a high turnover of staff, which led to Mr O'Brien having concerns about pupils' performance.
"Mr O'Brien explained how his personal background had impacted on his actions, which he explains motivated him to protect the pupils from the emotional consequences that may follow if those pupils didn't achieve the results they desired," the panel said.
"Although there may have been difficulties in the school, and the panel is sympathetic to the background issues described by Mr O'Brien, the panel did not consider Mr O'Brien was acting under duress.
"Mr O'Brien, as head teacher, was in a senior position and should not have allowed such matters to influence his actions."
The panel recommended that Mr O'Brien should be made subject of a prohibition order indefinitely and could apply for it to be reviewed after five years.
The recommendation was supported by a Department for Education official on behalf of Education Secretary Nicky Morgan.