Who is responsible for the regulation of the enforcement in the UK?

Step forward the CAA, whose "light-touch" regulation would make being mauled by a dead sheep look like a terrifying encounter.

Until this national disgrace is sorted out, you have to be responsible for your own enforcement.

Don't mess around with lots of correspondence. Write the airline one letter setting out full details of the claim, providing where appropriate copies of all receipts. State the if the claim is denied, you want full details of the basis on which the airline contends compensation is not payable. Set a deadline for response of 28 days and warn that if you don't get a response within that period you will commence proceedings in the Small Claims Court.

If you don't get a response, off you go.

If you do get a response, and it is along the lines of the above, you should reject the contention that this discloses "extraordinary circumstances" and state that unless they pay the EU Compo within 14 days you will commence small claims proceedings.

It's like bank charges. Things will only change if people take action. If people take action in sufficient numbers eventually there will be a test case and the law will be clarified.