Definitely not.
Admissions teams make their decisions based on an applicant’s ability to meet the entry requirements, their enthusiasm for the subject area, and potential to succeed on the course. It is unlawful, under the Equality Act 2010, to refuse a student a place or treat them less favourably because of an impairment or health condition. Find out more about the Equality Act 2010 from Disability Rights UK.
Remember, it is optional to give details on your UCAS application, and you can contact the university or college to share this information after you have received an offer if you feel more comfortable. However, please remember it is important to do this as early as possible.
Disability Rights UK discuss this issue and offer insight about being open about disabilities in their guide Into Higher Education.