EIM26101 - The benefits code: beneficial loans: general
Part 3 Chapter 7 ITEPA 2003
An employee can obtain a benefit when provided with an employment-related cheap or interest-free loan. The benefit is the difference between the interest the employee pays, if any, and the commercial rate the employee would have to pay on a loan obtained elsewhere. Such loans are called beneficial loans.
An employee can also benefit if an employment-related loan is released or written off. He or she is then no longer obliged to repay the amount that was lent.
There are special rules relating to the taxation of these benefits.
The relevant guidance is: