detector

They have called for knife arches, similar to the metal detectors used in courts and at airports, to be installed in secondary schools, saying they "didn't want anyone to go through what we have".

The rats can check an area the size of a tennis court in about 30 minutes, the charity says, whereas a human with a metal detector might take four days to clear the same land.

Ron Walters, 76, from Kingswinford, West Midlands, found the coin with his metal detector in Wall Heath near Dudley last year.

He says he was scouring a field with a metal detector on the Danish island of Taasinge, when he unearthed the metal object.

When discovered by a police officer with a metal detector on a cold November morning last year, the iPad was found caked in mud having been underwater for more than five years.