Gnawing the Big Apple

Zero tolerance" was the name given to a controversial crackdown on crime in New York... and the city has now launched another campaign along the same lines. Only this time the target is not criminals, but rats. Experts from across the United States met in New York last month for the first ever rat summit. As the BBC's Damian Fowler reports, academics, politicians and pest controllers have joined forces to try to curb the soaring rat population: