Exam boards should be banned from endorsing textbooks and training courses to prevent the "aggressive commercialisation" of education, a leading headmaster has warned.
John Wood, the incoming chairman of the Independent Schools Association, said it "cannot be right" that examiners are "allowed to make money" from teaching materials and seminars.
Insisting school staff should be accorded greater freedom to select teaching materials, he said the provision of training courses by examining bodies created an "uneven playing field" only open to those willing to pay.
His comments came in the wake of an investigation of the system by regulator Ofqual following allegations that teachers were being given advice at £230-a-day seminars on how students could score higher marks in tests.
Wood, headmaster of Dixie Grammar School in Market Bosworth, Leicestershire, warned safeguards proposed by exam boards were insufficient and would do little to improve the system.
"The aggressive commercialisation of the exam system has seriously undermined its integrity," he said.
"It cannot be right that exam boards are allowed to make money from textbooks and training seminars. This commercial activity needs to be more tightly regulated.
"This will raise standards by allowing teachers more freedom to choose high quality materials in support of pupils' learning."
Insisting that the provision of exams should be separated from the provision of seminars and training courses, he added: "Such training is only open to those willing to pay, and this creates an uneven playing field for schools."
Among his proposals is the suggestion that examiners, and especially chief examiners, should be barred from claiming any link to an exam group to help promote their own commercial interests.
"Whilst we welcome the exam boards' apparent willingness to overhaul procedures, the safeguards they propose are not sufficient, as the industry will still be largely policing itself," he added.
Wood, who has been appointed chairman of the Independent Schools Association (ISA) for 2012, also recommended the reintroduction of "proper oversight" of exams by impartial panels - each comprising teachers, chief examiners and university representatives - to ensure standards are maintained across all subjects.
Three examiners, two from the Welsh exam board WJEC and one from Edexcel, were suspended following inquiries in December into claims teachers were given unfair advice and told that one exam board set easier tests.
Undercover reporters at the Daily Telegraph attended 13 seminars run by exam boards, the newspaper reported.
It was alleged that during these sessions, teachers were "routinely" given information about forthcoming questions, words or facts that students should use to gain marks, and areas of the syllabus that teachers should focus on.
Responding to last month's report, Education Secretary Michael Gove warned "larger-scale reform" of exams may be necessary in the future.