I understand the basic principle of Promissory estoppel, however what I don't get is the "sword and shield" rule.
If for example I say to someone I can give you a free holiday, but I receive no consideration (money or any kind of benefit). If I then cancel that holiday they can then invoke Promissory estoppel against me and force me to give them that holiday.
What I don't understand then, is if Promissory estoppel can only be used as a defence and not a claim, where would the person who I have promised the holiday to start their claim?
Also if I claimed that certain circumstances prevented me from fulfilling that promise (ie. bad weather, floods, sold holiday on for profit) would I still be liable?
Thanks