How the minimum wage is worked out
The minimum wage is checked across each pay reference period — usually a week or a month — not shift by shift. Your total pay for the period, minus certain deductions, is divided by the hours you worked.
Deductions for things you need for the job, such as uniform, your SIA licence or required training, count against your pay for this check. If they take your average below the minimum, you've been underpaid.
If you've been underpaid
Raise it with your employer in writing first. If it isn't fixed, you can complain to HMRC, which enforces the minimum wage, or call Acas on 0300 123 1100 for free advice. Your employer has to pay back the arrears.