For regional and national news, they get them from Reuters, AP, or other newswire services. (In fact, in the US, that's where local papers get most of their content.) For stock photography for illustration and editorials (as opposed to reporting), Getty is very common. But, most surviving local papers do have in-house photographers, either on staff or as contracted freelancers.
For example, from today in the paper of the midwestern town where I grew up, an AP story on the presidential inauguration AP photo, and a local story on budget cuts with a local staff photo.
This is a small paper (circulation around 30,000), but there's a whole photo department listed on the contact page, including a Chief Photographer, two Photographers, and a Photo Intern. The newspaper in a smaller neighboring town (circulation 12,000) still has one photographer on staff. I imagine the situation is similar over on your side of the Atlantic.
The first personnel listing gives you an idea of how to get a foot in the door, by the way — internships. That link goes to the New York Time's photo intern position, which is probably highly contested. I expect that the larger newspapers (and the newswire services) usually fill their ranks from photographers who started on the smaller ones.