Complaints concerning unauthorised deductions from wages must be made to an Employment Tribunal and "not otherwise" (ERA 1996 s.205(2)). Errors in computation of wages do not count as "deductions" for this purpose (ERA 1996 s.13(4)).

There are various situations in which a tribunal does not have jurisdiction to consider an "unlawful deduction from wages claim". These include a claim where the deductions were required by statute (eg PAYE and NI contributions) or where the worker had authorised the employer in writing to make payments to a third party out of his wages. The various situations are set out in ERA 1996 s.14

A claim for unlawful deduction from wages can be made only if it is a claim for a specific or ascertainable sum of money. If the amount is uncertain (for example where an employee claims he was legally entitled to a bonus but cannot say how much that bonus should have been as the amount was discretionary) then the claim will be for damages for breach of contract and in that event an employment tribunal would not normally have jurisdiction (see Employment tribunals/contract claims ).

See also notes at Time-limits/for various applications to Employment Tribunals/unauthorised deductions from wages claims and/or Employment tribunals/jurisdiction of/extension to breach of contract cases .