Did you know, if you apply for a shotgun, the government via the police cannot stop you from owning one. They have to have a reason to decline a shotgun certificate. So the only person that can stop you, is you. So if you have a clean police history, nothing on your driving record that would affect the outcome (say caught using your car as a weapon, deliberately driving at someone), your medical history is fine, and the referees you give check out, then you can go buy a shotgun. If you fucked up on any of those, then you've given the police to not grant you a certificate.
If you want a fire arm, such as a long barrel handgun, a rifle, an Uzi etc.. then it's up to you to prove you need one. So if you have a clean background, your job as a pest controller requires one, you're part of a gun club, you have the land and vermin that requires one etc... , then it's likely you will be granted one. If you want one because you're paranoid about violence and thus need it for self defence, or you just like the look of a rifle, then forget it mate.
And if you are declined, yet you're squeaky clean, and good reason for a firearm, I can guarantee it you would get a fair trial in the UK if you sued the government and/or police, because the judicial system is so anal in following the law, even the government lose court cases.
So now your knowledge is updated, your future posts will reflect this. But as you are American........no fucking chance.