It can be converted into a binding contract by the simple response ‘I accept’.

From this, it follows that offers should be unconditional and unqualified, not

requiring further discussion or negotiation to establish what degree of

commitment is being given. Equally, the proposal must be made with

(objectively determined) legal intent. In Carlill v Carbolic Smoke Ball Co,13

during November 1891, the manufacturers of a medicinal preparation called

the ‘Carbolic Smoke Ball’ placed a number of advertisements in magazines

and newspapers to the effect that the product would be highly effective in

warding off the effects of, and indeed would ‘positively cure’, a range of

ailments, including influenza. Moreover, they stated that if used as specified

(three times a day for two weeks), they would guarantee the prophylactic

effect of the smoke ball and would pay .100 to anyone who, despite using it as

specified, still contracted influenza ‘or any disease caused by taking cold’. Mrs

Carlill bought a smoke ball from a chemist and used it as directed, but still

contracted influenza. She sued the company for the .100 promised. Amongst

13 [1893] 1 QB 256, CA.