Johnson v Agnew [1980] AC 367 is a landmark English contract law case on the date for assessing damages.

Five major principles it laid down were, The 'commonplace, indeed routine'[1] facts were that Mrs Adeline Agnew twice failed to complete purchase of Michael and Renee Johnson's farm, Scheepcote Grange, Woodburn Common, Buckinghamshire.

Lord Wilberforce said, The general principle for the assessment of damages is compensatory, ie that the innocent party is to be place, so far as money can do so, in the same position as if the contract had been performed.

But this is not an absolute rule; if to follow it would give rise to injustice, the court has power to fix such other date as may be appropriate in the circumstances.

Whatever contrary indications may be disinterred from old authorities, it is now quite clear, under the general law of contract, that acceptance of a repudiatory beach does not bring about "rescission ab initio".