You should really see a dentist to ask if a referral to an orthodontist is appropriate
Just as a guide this is from the NHS website
NHS orthodontic treatment is free for people under the age of 18 with a clear health need for treatment. But because of high demand, there can be a long waiting list. NHS orthodontic care isn't usually available for adults, but may be approved on a case-by-case basis if needed for health reasons. A rating system known as the Index of Orthodontic Treatment Need (IOTN) is used to assess your eligibility for NHS treatment. The British Orthodontic Society's website has more information about the different grades used for the IOTN. NHS treatment is available for grade 4 and grade 5 cases. Grade 3 cases are usually judged on an individual basis. Treatment may also be made available if the appearance of a person's teeth, jaw or face is of concern.
Approximate cost is £3000 if the NHS doesn't do it