Salary sacrifice occurs when you agree to give up part of your salary for an agreed period of time in exchange for a non-cash benefit, such as the supply of home and tech equipment. As salary sacrifice is taken from gross salary (before tax) rather than net pay, you will not initially pay any tax or National Insurance on the salary sacrifice amount.
However, the provision of the equipment is a taxable Benefit In Kind (BIK) that needs to be reported to HMRC on a P11D benefits form at the end of the tax year. A P11D form is used by employers to report any employee expenses, Payments and Benefits to HMRC, e.g. technology equipment, company car and private health insurance. Therefore, HMRC will recover the tax due, in arrears, via a change in your tax code the following tax year (April 6th – April 5th), you will still benefit from an NIC saving; up to 8% for basic rate taxpayers and 2% for higher rate taxpayers.