The main effect of Employment Rights Act 1996 Part II (ERA 1996 s.13 to ERA 1996 s.27) is to make it unlawful for an employer to make any deduction from the wages of a worker employed by him unless the worker has agreed in writing to the deduction being made or it is required by law (eg deductions for PAYE and national insurance).
If an employer reduces or fails to pay wages without agreement in writing this amounts to an unlawful deduction from wages even if the employee owes money to the employer. In other words, the employer is not entitled to take the law into his own hands. Thus if, for example, an employee does not return property belonging to the employer after being dismissed, perhaps a computer or some safety clothing, the employer is not entitled to deduct the value from the final wages payment due unless the employee has agreed in writing that this can be done.
"Wages" includes any fee, bonus, commission, holiday pay or other emolument referable to his employment, whether payable under his contract or otherwise (ERA 1996 s.27 and see notes at Deductions from wages etc/meaning of ''wages'' ).
The rules do not of course remove an employer's right to recover money properly due to him from an employee (eg typically to recover an overpayment of expenses or wages). What they do mean is that, save in a few special cases, the employer is not allowed to recover the money by taking the law into his own hands and deducting it from future wages without consent of the employee (see Deductions from wages etc/deductions from wages, salary or pay/general rule (basic position) and Deductions from wages etc/deductions from wages, salary or pay/general rule (exceptions) ).
Given the difficulties of bringing an equal pay claim under the sex discrimination legislation (see Sex discrimination/equal pay and terms of employment/a general introductory note and Equality Act 2010/equal pay and terms ), it may sometimes be more appropriate for a person who considers that she (usually) could make such a claim to bring it instead under the unlawful deduction from wages provisions of Employment Rights Act 1996 (see notes at Sex discrimination/equal pay and terms of employment/relationship with wrongful deduction from wages rules ).
See generally notes under this main head Deductions from wages etc and in particular at Deductions from wages etc/deductions from wages, salary or pay/penalty for improper deductions from wages .