For entitlement to SSP to be considered, an employee must tell
their employer that they are absent from work due to sickness.
Employers can make their own rules as to when and how they are told that the employee is unfit for work but regulation 7 of the SSP (General) Regulation 1982 restricts these rules for SSP purposes.
Employers cannot insist that the employee tell them:
If the employer has no rules about notification of sick absence, the employee or their representative must tell their employer of any day they are unfit for work within seven days. If they do this by post they are treated as having given notice on the day they posted it.