Setting Up HMRC Government Gateway for Payroll

Every employer who runs payroll in the UK needs HMRC Government Gateway credentials. These are separate from any accountant or payroll bureau login — they are your organisation's own access to HMRC's online services, tied to your employer PAYE reference number.

Setting up Government Gateway for the first time involves registering as an employer with HMRC, receiving your PAYE reference, and creating Government Gateway credentials using that reference. HMRC sends an activation code to your registered address by post — this is the step that catches most first-time employers out, as it takes up to five working days and payroll cannot submit until it arrives.

Once activated, your Government Gateway user ID and password can be stored securely in Mellow. When you run payroll and approve a pay run, Mellow uses those credentials to submit your Full Payment Submission (FPS) to HMRC automatically. If you change your Government Gateway password — which HMRC encourages periodically — update it in Mellow at the same time. A mismatched credential is the most common cause of a failed RTI submission, and a failed submission means a late filing penalty can follow.