How to appeal
[ch 3: pages 20-21]If your employer decides you are not entitled to SSP and you disagree, the employer must give you the reasons for the decision in writing. You can appeal against the decision to HMRC within six months of the refusal to pay. You will need to state the period for which you are claiming SSP and your employer’s grounds for refusing to pay. You can write directly to HMRC to pursue your claim if your employer refuses to provide anything in writing.
A claim for unpaid sick pay (SSP or contractual) should be brought as a claim for unlawful deduction of wages in the employment tribunal or as a claim for breach of contract (failure to pay your wages) in the civil courts — usually the small claims court. However, only HMRC can resolve a dispute over whether you are entitled to SSP.
More information about taking an employment tribunal claim can be found at: https://www.gov.uk/employment-tribunals/make-a-claim.
You can find more information about bringing claims in the civil court at: www.gov.uk/make-court-claim-for-money/overview.
You should contact your trade union for advice if you are considering making a claim.