I've researched this quite thoroughly as I wanted to be a paramedic too for a while - for the majority of uni courses on either Paramedic Practice or Paramedic Science (you will need one of these to become a paramedic) you will need a Biology and a Chemistry A-Level. This just makes the course at uni so much easier. On the other hand if you don't go to uni for Paramedic training, you could always try for the internship option, but chances come few and far between. You will also be 1000x more likely to get offered a job as a paramedic if you have copious experience volunteering with St John's Ambulance or the Red Cross or some other health organisation, and if you have first aid qualifications already. Good luck!