A teacher has been jailed for three months for tampering with test papers at two primary schools.
Mercer took over as headteacher at South Borough in September 2001
Alan Mercer, the former head teacher at South Borough Primary School in Maidstone, Kent, was sentenced at Maidstone Crown Court on Friday.
He pleaded guilty in January to 10 offences of forging Key Stage 2 assessments at South Borough in 2002.
The 46-year-old also admitted two charges of forging Key Stage 2 tests at Eythorne Elvington School in Dover and two charges of forging PESE Grammar School entrance exams at South Borough in 2002.
Mercer, of Prospect Row, Gillingham, Kent, had also asked for a further 140 offences of forging test papers to be taken into account.
It undermined the children and undermined the school to which you were devoted
Judge Keith Simpson said the case was "so serious" that an immediate custodial sentence was required.
He said: "If others were to act in this fashion the whole system would be immediately and utterly destroyed, and that cannot be allowed to happen.
"It must also be made plain that this was something that, however well intentioned, did very much more harm than good.
"It undermined the children and undermined the school to which you were devoted."
The court had heard the teacher had felt under pressure from the publication of league tables and financial difficulties at the school.
Mercer took over at South Borough in September 2001 after five years at Eythorne Elvington Primary School.
An Ofsted report for South Borough just a few months before his arrival had described the quality of teaching as "satisfactory" but pointed to particular problems in Key Stage 2.
Suspended as headteacher
In the summer term of 2002, concerns were raised by the Qualifications and Curriculum Authority over some of the Key Stage 2 SATs test papers from the school.
The local education authority announced it was investigating the school tests, which help the government publish league tables, and voided the results.
Mercer was suspended as the investigation progressed over the summer holidays and Kent County Council gave its findings to police.
During the investigation it was discovered Mercer's tampering dated back to his previous school.
Drop in pupil numbers
Evidence was also uncovered that grammar school entry tests at South Borough, formerly the 11-plus, had also been forged.
Mercer was arrested in October 2002 and resigned.
Outside the court, the chairman of governors at South Borough, Philip Sayer, said: "I am pleased he got a custodial sentence and I hope that this will send out a clear message to schools everywhere that it is not right to mess about with children's efforts in this way."
He said the school had already seen pupil numbers drop by 42 on last year when Mercer was in charge as a result of negative publicity.