Ministers are to encourage the police to crack down on men and boys who have sex with under age girls. The plans are being drawn up in response to a fall in annual prosecutions from 545 in 1985 to 272 in 1995. The move comes after a week in which one 12-year-old from Rotherham gave birth and another from Sheffield became pregnant. Police are set to interview the 14-year-old boyfriend of the second girl, who has blamed sex education lessons at school.