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HMRC internal manual

National Insurance Manual

Earnings Periods: Employee earns a fee for each session they work: Separate fee paid for each session worked

If an employer pays an employee a separate fee for each session they work, the earningsperiod is the length of the session or a week if that is longer. If the employer makesmore than one payment at different times in the same week, work out NICs separately oneach payment.

See NIM09910 if the employee is an irregular harvest worker.