If you have no concerning issues on your police record, and on your driving record, and in your medical records, and you just have a reasonable reason to own/use one, then you're welcome to own and use one in the UK.
What you claim to be law abiding in the US, would likely fail in the UK. To be law abiding, your reason wouldn't be for the defense fallacy, willing to shoot others. You would fail if you do not secure your firearm in a secure cabinet. You would fail if someone else (even your spouse) gets access to the cabinet key and know it's whereabouts.