Discuss when a breach of contract brings a contract to an end.

“An act of acceptance of a repudiation requires no particular form…. It is sufficient that the communication or conduct clearly and unequivocally conveys to the repudiating party that the aggrieved party is treating the contract as at an end.” (Vitol Sa v Norelf (1996,HL)) Citing relevant cases, discuss when a breach of contract brings a contract to an end.