In Johnson v Unisys Ltd  1 AC 518 per Lord Steyn at para 20:
It is no longer right to equate a contract of employment with commercial contracts. One possible way of describing a contract of employment in modern terms is as a relational contract.
In Keen v Commerzbank AG  ICR 623, per Mummery LJ at para 43:
Employment is a personal relationship. Its dynamics differ significantly from those of business deals and of state treatment of its citizens. In general there is an implied mutual duty of trust and confidence between employer and employee. Thus it is the duty on the part of an employer to preserve the trust and confidence which an employee should have in him. This affects, or should affect, the way in which an employer normally treats his employee.