One in five trainee teachers cannot do simple sums or pass basic spelling and grammar tests.
One in ten have failed their final-year numeracy and literacy tests twice in a row, while dozens have needed an astonishing ten attempts.
One clearly innumerate trainee was allowed 37 resits to get through the maths paper.
Critics said yesterday those who take multiple resits should not be teaching and will have a detrimental impact on their pupils.
From next year, Education Secretary Michael Gove is limiting the number of retakes to just two.
Trainees have to pass basic skills tests in literacy, numeracy and ICT (information and communication technology) before they qualify for the classroom.
The pass mark is a modest 60 per cent.
The latest figures from the Training and Development Agency for Schools reveal that in 2009/10, a fifth of trainees failed both the numeracy and literacy tests first time round.
Some 6,957 failed literacy and numeracy on the second attempt, while 1,508 failed either discipline on their fifth attempt.
More disturbing still are the vast number of resits some trainees have been granted before passing. One took 37 tries to pass numeracy and 57 would-be teachers passed only on their 19th attempt.
Standards have fallen during the last five years.
Of the 32,717 trainees who passed their numeracy test in the academic year 2003/4, 83.6 per cent did so first time.
And of the 33,412 trainees who passed their literacy test, 86.4 per cent did so at the first attempt.
Last year the figure was 80 per cent for both. Under Mr Gove’s plans, woefully poor trainees will no longer be allowed in the classroom.
His policy would have weeded out 1,963 for poor literacy and 2,939 for poor numeracy last year. But critics say his crackdown does not go far enough.
Passing the numeracy test has been a requirement of Qualified Teacher Status since 2000. Passing tests in literacy and ICT were made compulsory the following year.
Students sit the online tests in the final year of teacher training. They were originally allowed just four or five attempts to pass. But Labour scrapped the rule in 2001 to allow unlimited resits.
Professor Alan Smithers, director of the Centre for Education and Employment Research at Buckingham University, said: ‘It’s shocking we have allowed people to become teachers who don’t fully grasp our language or handle numbers and who we have let slip through the net on the 37th attempt.
‘The nature of tests is that ... people will be able to fluke them, which means they pass but have no proper understanding of the subject – much like with driving tests. Three attempts will reduce this possibility, but it does not go far enough.’
NUMERACY TEST QUESTIONS INCLUDE:* Teachers organised activities for three classes of 24 pupils and four classes of 28 pupils. What was the total number of pupils?’ [184]
* A teacher completed an 18km sponsored walk for charity. Thirty pupils sponsored the teacher 5p per kilometre. How much did the teacher raise? [£27]
And in literacy, trainees were asked:
* There were no [blank] remarks at the parents’ evening. Is the correct word: dissaproving disaproveing dissapproving disapproving? [disapproving]