Phlebotomists are healthcare professionals that work as support workers, collecting blood samples from patients.
Many phlebotomists work as part time nurses, others as full time healthcare assistants.
There are no minimum requirements to become a phlebotomist in UK, even though good results at GCSEs would be an advantage. Often the training is done at the job, before you start your work as a phlebotomist, but one can also have the training and certification beforehand.
After the training you will be awarded a certificate of competence, making you fully qualified phlebotomist. These kind of qualifications will help you find jobs in various hospitals, not only in the place where you got the training.