I live in London, fairly near one of the most affected areas.
Firearms are not an option for the law abiding.
I know of places from where an illegal gun could be obtained, but would not take the chance.
The police take illegal firearms very seriously indeed.

I have however armed myself with a crossbow, which I believe to be legal to posses.
Carrying it in the street would not be allowed, but for home defence I might be tempted.