For Graham Sharpe, his rat problem started with a persistent gnawing he heard one evening in his kitchen. Sharpe, a 52-year-old academic at Nottingham Trent University, ransacked the cabinets and replaced an external drainpipe which he thought might be an access point; but the furtive scratching and chomping continued. Then one night as he and his wife were lying in bed, they suddenly heard a deafening scuttling across the bedroom ceiling directly above their heads.
