Once an offer is made and accepted a legally binding contract exists - the offer and acceptance represent a 'meeting of the minds' alongside legal capacity and intention to create legal relations (consideration of course, in this case was either £2m or £200k). We're all familiar with the stories of misprints in advertising when the supplier has to stand over the price for those who accept the offered price before the supplier realises the mistake and rescinds the offer. Well, that's what the professional training says but the High Court judgement in the above case appears to have rewritten that fundamental of contract law.
The case came about as a result of the commodities trader, Kai Herbert, recognising a mistake had been made by JP Morgan Chase, and his decision to accept the contract in the knowledge that a mistake had been made. He then didn't turn up for work, JP Morgan then rescinded the offer and Herbert took a case against JPMC for loss of earnings. You couldn't make it up. The court ironically has ruled in favour of JPMC.
We now have potentially interesting implications for procurement.