|Information revealed by the Criminal Records Bureau (CRB) has shown that over 4,000 offenders, including rapists, paedophiles and drug dealers, applied to become teachers last year.
Released to the Press Association after a request to the CRB the figures show that checks have prevented more than 130,000 unsuitable people from working with children or vulnerable groups.
The Association of School and College Leaders says the number of offenders who apply to teach is "very small".
It also said it is extremely encouraging that the system is picking up people with convictions.
In 2011, 263,000 people who applied to become teachers had CRB checks done with 1.5% of them being rejected on grounds of previous behaviour.
Those rejected had almost 9,500 previous offences between them, including 50 sex offences, 11 for arson and two for making threats to kill.
Separate figures also show that sex offenders and hundreds of violent criminals applied to work in nurseries last year.