The House of Lords issued judgement in the case of Chartbrook Limited v Persimmon Homes Limited and Others [2009] UKHL 38 on 1st July 2009. In this case the House of Lords were asked to consider the disputed definition of an element of the contract price within an agreement between the parties for the development of a plot of land for residential and commercial purposes.

Overruling the decision of the Court of Appeal and favouring the construction of the defendant Persimmon Homes Limited, the Lords allowed the appeal on grounds of rectification. Applying the principles set out in Frederick E Rose (London) Ltd v William H Pim Jnr & Co Ltd [1953] 2 QB 450, 461 both parties were mistaken in thinking that the agreement reflected their prior consensus. Persimmon was entitled to rectification.

In the course of the judgement the Lords held that there was no clear case for departing from the rule that prior contractual negotiations are inadmissible. Following the judgement in R v National Insurance Comrs, Ex P Hudson [1972] AC 944, 966 the Lords confirmed that power to depart from the exclusionary rule would only be applied where previous decisions of the House were thought to be impeding the proper development of the law or were contrary to public policy.