University of Manchester - Interviews

Hey guys, I have applied for BSc (Hons) Physics with Astrophysics at University of Manchester and the website says there "may" be an interview and nothing else really. I am also applying to Cambridge but I was wondering what the interview for Manchester would be like. Is it similar to Cambridge? Academically rigorous and they essentially grill you or is it little bit more relaxed? What's the format like and does everyone who get accepted get called for an interview? Any help is much appreciated!