Only mistake as to promise
is sufficient, not eg mistake as to quality or substance.
Seller offered to sell buyer, by sample, parcel of
oats at certain price.
According to buyer, seller described oats as ‘good old oats’.
Seller denied word ‘old’ used.
Buyer counter-offered with lower price.
Accepted by seller’s delivery of oats.
Found to be new oats when delivered – unsuitable for
Court of Queen’s Bench held that in order to relieve
buyer, seller must have known:
(i) that buyer believed he was buying old oats, and,
(ii) that buyer believed seller was contracting to
sell old oats.