The airport is a secure restricted area. It is governed by various statutes and also by bylaws that you agree to observe and comply with when you enter. You have no right of entry.
From what you have said, because of the delays to your flight you elected not to travel and asked for somebody to escort you out of the airports restricted security area. Your complaint is with the length of time it took for somebody to become available to assist you in your request.
Nobody forced you into that situation against your will, or held you in that situation in order to violate a law, so I think you would have a difficult case convincing anybody that you were falsely imprisoned? Nobody refused to assist you, and it was not inconceivable that it took some time for anybody to become available to assist you in your request.
I am sure you can bring it to the attention of the airport operator (BAA) for a better explanation, and a solicitor can better advise you regarding your legal enquiry. I would have thought a snowball in hell would have a much better chance than your assertion of "false imprisonment" though?