Black Rats in UK.

[montagu]

Afaik the only Black Rat colony still surviving in the UK now is in the Shiant Isles of the Outer Hebrides.

But occassionally there are sightings of Black Rats in other places. Does anyone know of any recent discovered colonies elsewhere?

[Dorts]

As you probably know, they were until recently on Lundy Island from where they were eradicated. It's possible a small colony still persist's there.
There are also occasional sightings in a few dockyards. And the recent find of six in Truro, Cornwall by a Pest Control Officer.
So it's always possible that a few other small populations exist and go un-noticed.
Dorts.