For many years, across the world, the extraordinarily powerful noses of dogs have been successfully used to help detect crime.
Now, in Britain, moves are under way to recruit humans to perform the same subtle work.
Police are encouraging the British to step out of their homes, raise their nostrils aloft, and see if they catch the whiff of wrongdoing wafting from the next-door neighbors.
Visitors to these crowded islands are often charmed by the small redbrick terraced houses that are in every town and city.