[...]

An offer, again, must be capable of creating legal relations. It is for the parties to See to it that the offer is such that, when it is accepted, a contract is formed; the Courts, as we have seen, will not constrtuct a contract for them out of terms which are indefinite or illusory . A bought a horse from X and promised that 'if the horse was lucky to him he would give £5 more or the buying of another horse': it was held that such a promise was too loose and vague to be considered in a court of law.