Speaking at the seminar in central London, Prof Tombs said many undergraduates had been taught to write essays at school simply to pass tests.
"One of the things that one notices in student essays is how much damage has been done by the imposition of artificial structures for essay writing,” he said.
“They've been drilled into writing a particular way, making particular kinds of arguments in a particular order and not writing their own ideas or responding to questions in a fresh and original way, and that's very damaging, and it's very visible.”
Addressing the same event on Monday, Prof Abulafia said he was “worried about the increasing evidence that undergraduates when they arrive, even at Cambridge, don’t seem to know how to write essays”.
‘People who are undoubtedly extremely bright are grappling with difficulties in that area which once upon a time would have been inconceivable even among the weaker brethren and sisters,” he said.
Last week, the former head of an exam board warned that too many students were gaining A grades in GCSEs and A-levels after being “taught to the test” at school.
Jerry Jarvis, who led the Edexcel board for four years, called for a radical overhaul of the grading system because top marks "no longer automatically mean top students”.
Speaking on Monday, Prof Abulafia said that writing essays involved “making judgments” but too many pupils struggled to cope because of the emphasis on chasing decent exam grades.
He said that pupils often “knew the mark scheme by heart and that is how you ensure you get an A".
"That is not what education is about," he said.
"What we've got to do is educate students and also examiners in handling the sort of work which involves making judgments, trying to say something that's slightly different about familiar topics."
Addressing the same conference, John McIntosh, a Government adviser, said teachers were increasingly acting ike robots, teaching children the minimum they needed to pass tests.
Mr McIntosh, former head teacher of the London Oratory School, West London, which was attended by two of Tony Blair's sons, said staff were working "slavishly" to the demands of the national curriculum and the demands of league tables.
"We are where we are, partly because, I have to say, of the national curriculum,” he said.
"I find that teachers have become increasingly robotic, they have worked slavishly to the national curriculum, to the prescribed curriculum, they have worked slavishly to the demands of the league tables etc and a lot of the teaching is not very sort of, instrumental, and children are taught a lot of facts, completely out of context often, simply the minimum required for whatever the next test or examination will be."