NIM08220 - Earnings Periods: Employee earns a fee for each session they work: Payment made irregularly and no regularity found
Regulation 4 of the Social Security Contributions Regulations (2001) (SSCR 2001) (SI 2001 No 1004)
If an employer pays an employee a fee at irregular intervals for each session they work and neither NIM08200 nor NIM08210 apply, the earnings period is the interval between the payments or a week, if that is longer.
See NIM09910 if the employee is an irregular harvest worker.