It is not necessary nor appropriate to ask airline to facilitate your exit. You have the right to leave at any time.
Then if the LGW airport is different in that, someone should explain exactly how and why.
This was more or less what I thought. Surely it should be the airport security who facilitate exit, not the airline? I did ask the BAA security people if I could leave by the way I came in but they told me I couldn't. I asked them on what authority they could hold me, to which they said if I argued then they would call the police. So I asked them to call the police, at which point they started to get quite aggressive.
By the way I am not thinking of really taking them to court, I am just intrigued that BAA seemed to think it within their remit to hold me airside.
From what you have said, because of the delays to your flight you elected not to travel
Not correct - my flight was cancelled. The airline broke their contract with me, not the other way around.