Loads. Professor J.A.G. Griffith of the London School of Economics once said that "The Constitution is what happens". It is constantly evolving and being developed with the passage of every law and every administrative decision made by ministers and others. People sometimes say that the UK does not have "a constitution" or that it does not have a "written constitution", but what they mean is that it is not codified in a single document and entrenched by a special procedure.
Yea, indeed, verily, we do not have a specific constitution written into a single document, but that doesn't mean that we "don't have one", or even that we don't have a written one. Our written constitution is written in laws, books, text-books, students' essays, newspapers, magazine articles, and in the hearts of every British subject of Her Majesty... TTML GAB and OVS