1. 'The absence of a written constitution ... enables constitutional change to be brought about within the United Kingdom with the minimum of constitutional formality.'

(Hilaire Barnett, Constitutional and Administrative Law, 10^th edition, 2013, Routledge)

Describe and give examples of the sources of the UK constitution. Explain how each source maybe changed and refer to Barnett's statement. Give your opinion on the extent to which the UK has a flexible Constitution.