Hello again. Thank you for responding so quickly to my previous question, I did try to find a way to comment rather than add a new question but maybe it isn't possible.
I think by using the example of a car park sign maybe I caused confusion.
I am more interested in how a sign can meet whatever necessary requirements there are to be considered a binding contract.
If, for instance, I put a sign up next to my front door that said that by inserting unsolicited mail or advertising leaflets that lacked a specific occupant's name through my letterbox then you enter into a contract to pay me £1 per delivered item towards upkeep and maintenance of the door and its letterbox...
Well, even if I could identify the delivery person I doubt I would get far chasing for money. Because people would / could argue that my sign assumed that they could read and understand English when there's no legal requirement for them to do so. As in my previous question, they could argue that expecting them to agree to a contract when I have no way of being sure that they even know what a contract is, let alone that they understand and agree to the terms of this particular one would (to my admittedly untrained mind), be a strong argument in favour them being excused from any action.
I put car parks because they seem to be able to put up a sign and have it be a contract, but surely there must be more to it than just putting up a sign? It cant be that simple... can it? Otherwise, everybody would be doing it!
If all the elements of a contract are present (offer/acceptance, intention to create legal relations, consideration, certainty, etc) then I don't see why, in principle, an English law contract couldn't be formed through the act of posting a letter. But you have to bear in mind that the courts can use the legal principles as tools to reach the result that they want. Taking your example, you could argue that, unless the person posting the letter is the person who benefits from the junk mail - unlikely - then there is a failure of consideration.
For background on the elements of a contract, see:
This is an interesting question, but unfortunately I don't have the time at present to research this or write a comprehensive answer.