Investigations into high-school exam cheats increased more than 50 per cent last year, and two students had their results withheld for "collusion".
Last year, 336 breaches of the examination rules were investigated, up from 208 reported in 2005, Qualifications Authority figures show.
Among the investigations were 10 foranswer booklets allegedly being altered before being sent in for reconsideration and 33 for writing offensive or inappropriate comments on answer booklets.
Two candidates were investigated for using their mobile phones in an exam, and there were 56 incidents in which candidates were discovered with their cellphones turned on.
Deputy chief executive of qualifications Bali Haque said 138,260 candidates took exams last year, so the breaches accounted for a "very small" percentage of the total.
"The increase indicates some students need reminding of exam rules and procedures," he said. "We will be again reminding schools and candidates of the rules and procedures before this year's examinations."
He said 135 students were punished by having some or all of their results withheld. Others were issued with warning letters.
Mr Haque said exam supervisors were encouraged to report all possible breaches, no matter how minor.
Exam cheats 2006
336 breaches of exam rules investigated
135 cases in which candidates had results withheld
56 candidates took mobile phones into the exam room
10 were investigated for allegedly altering answer booklets sent in for reconsideration
33 were investigated for offensive or inappropriate comments on answer booklets
