Rats are not indigenous to the UK. The first rat, Rattus Rattus or the Black Rat or Ship Rat came from India and arrived with the Romans during their occupation of England (43-410ad) . Despite being called black, some were light or dark brown.

The rat was unjustly blamed for spreading the Bubonic Plague.

Rattus Norvegicus– the Brown Rat or Sewer Rat – arrived in the 1700s and this is the rat you’ll see these days.

Despite the Latin name, the Norwegian connection is uncertain and the Brown Rat is believed to have come from China.

They don’t make themselves evident in the City except on the site of St Gabriel Fenchurch off Fen Court where they may be seen quite often, day and night.

The Brown rat is in the same category the Grey Squirrel and Signal Crayfish: a successful invasive species which ousted its incumbent counterpart.

In the UK the Black Rat was last recorded in the Hebrides in 2018 but is now probably extinct in the wild in the UK, though small colonies may survive on some offshore islands and across the river in Southwark. It is still bred in captivity and sold as pets or used in laboratory experiments.

SQUIRRELS

It amuses me that people will feed a squirrel but run away from a rat. They are very similar and both, of course, vermin. A squirrel is effectively a rat with a hairdresser and a PR agent.