 After Edward I's death Lamberton later swore fealty to his son Edward II promising to pursue the King's enemies, pay a ransom of £6000 in instalments and remain within the boundaries of the See of Durham.Lamberton saw his oath to Edward II as a necessity and extorted from him under duress, and therefore invalid.During his time in England, Lamberton stayed near the Tweed so that he could maintain connections with the parts of his diocese under English rule.