Do I need to provide an English language certificate if my degree was taught in English?
Only applicants who are either Nationals of a country which is deemed by the UKVI to be majority-English-speaking*, or who hold a degree or an equivalent qualification which was taught in a country deemed to be majority-English-speaking** will normally be assumed to have met the English language requirements.
* You are from a majority English-speaking country if you are a national of:
Antigua and Barbuda, Australia, The Bahamas, Barbados, Belize, Canada, Dominica, Grenada, Guyana, Jamaica, New Zealand, St Kitts and Nevis, St Lucia, St Vincent and the Grenadines, Trinidad and Tobago, United States of America
** If you have completed an academic qualification equivalent to a UK Bachelor's degree which was taught in one of the majority English-speaking countries listed below, you are normally exempt from additional English language requirements: Antigua and Barbuda, Australia, The Bahamas, Barbados, Belize, Dominica, Grenada, Guyana, Ireland, Jamaica, New Zealand, St Kitts and Nevis, St Lucia, St Vincent and the Grenadines, Trinidad and Tobago, The United Kingdom, United States of America.
Further information about english language requirements and a list of acceptable English language tests can be found at: http://www.qub.ac.uk/International/International-students/Applying/English-language-requirements/