In my view this is the gold standard of what a textbook should be.
This textbook is thorough, detailed, backs-up everything it has to say with strong and easily accessible sources, where there are conflicting views it presents them with balance and the authors avoid imposing their personal views onto the text either explicitly through what they say or implicitly by underhandedly giving more weight and attention to that they agree at the expense of what they do not - something I have seen becoming more common in textbooks.
The main flaw with this book is that its coverage is mostly limited to the specific operation of various institutions within the UK, often in almost painful detail. If that's what you need, it's an excellent book. However, if, as I was, you are reading this for a university course, it is likely that dozens of numbers on the operation of Parliament are not what you are looking for; rather, you want detailed coverage of constitutional debates and important judgments, where this is unfortunately lacking (it could just be my memory - mine was a library copy so easy reference is not possibly - but I don't remember Ghaidan v Godin-Mendoza being covered at all).
A very comprehensive and guiding light on this subject. sure to become a bible for any student. reading even chapters of this will help you to understand much of the furore and the seesaw type of progress being made for Brexit by our hapless Parliamentarians. But also good for answering those questions you thought of after watching the stage performance of King Charles III or its TV version! The rights duties and obligations of the Monarch, Parliament, the Judiciary and our role in the EU (boo! hiss!) all for you to learn about.
You'll never watch the news in the same way again.
A good textbook for information, but unfortunately is a bit lacking in analysis and commentary. The descriptions of the cases are good, but it would be nice if the authors provided some opinions and argumentation from both their own work and other prominent academic writers. It would certainly reduce the research workload.