Express and Implied terms of contract
However the terms of a contract are said to like "express terms" whether the parties themselves adverted to them on the time of negotiations and really agreed upon them as i.e. incorporated them with the contract so either verbally or in writing. Thus written terms prevail over unwritten terms. And hence handwritten terms prevail over others also.
Therefore a term that the parties did not expressly incorporate with the contract may nevertheless be deemed for be one of the terms of the contract through implication. Hence this may be necessary in order for "give business efficacy for the contract", such explained in The Moorcock. Otherwise the term may be implied through an Act of Parliament that the implied conditions and such warranties implied through the Sale of Goods Act.