Paragraph 32 of the Departmental Interpretation and Practice Notes No. 16 (Revised) clearly asserts that:-
"The Department accepts that interest-free and low interest loans provided by employers to employees are not chargeable benefits where the cost involved in providing the benefit is the sole liability of the employer. This acceptance is based on the understanding that the benefit received by the employee (i.e. paying less than the market rates) is not of itself convertible into money."
With the foregoing in mind, if the arrangement in your question is simply that your employer provides an interest-free loan to you, the interest expenses saved by you, under normal circumstances, should not be regarded as taxable income .