Errington v Errington and Woods 
- A father made his son and daughter-in-law a unilateral offer to his son and daughter in law that they could remain in the house if they paid off the remaining mortgage instalments
- They proceeded to do this, however before the mortgage was paid off, the father died
- The father’s wife inherited the house
- Could the wife remove the son and daughter in law from the house, given the father was dead?
- No removal, claim failed
- Although a unilateral contract can only be accepted once its conditions have been performed, the mother was estopped from revoking the offer as there was a collateral contract to keep the offer open until its conditions had been met
- It is uncertain if the wife was suing in the capacity of personal representative or executrix. If executrix, a licence successfully bound a successor in title, contrary to the orthodox land law licence rule set out in King v David Allen