No there's some sort of Sarah's law thingumy that allows women with kids to check out their potential new partner. But I'm not sure if it ever worked.
For what its worth most people I know in the police and probation don't want it. As it makes people over identify with being nonces and join the nonce underground. Like a sort of child molesting A team.
nb here's the wiki article which is quite accurate
http://en.wikipedia.org/wiki/Murder_of_Sarah_Payne#Sarah.27s_Law
I suspect the government will expand it and strengthen it. As the current multi agency system for nonce monitoring is unbelievably expensive and resource heavy.
in other news. Hull to control teenage pregnancy by turning all boys totally gay.