Britain’s Education Minister has promised to tighten child protection laws after admitting that she did not know how many registered sex offenders are working in schools. Ruth Kelly has been under pressure to resign since it emerged that her department backed the appointment of a physical education teacher even though he had a police caution for accessing child pornography. Child protection laws have been an emotive subject in Britain since Ian Huntley was jailed for killing two young girls from a school complex where he worked despite being a suspected sex offender.Police checks had failed to reveal his background. Under current laws it is impossible for ministers to automatically bar someone from working in schools who has accepted a caution for sex offences. But the government hopes new laws will make cautions and convictions identical – making it easier for authorities to keep track of suspects and offenders.