NIM21023 | Class 2 National Insurance Contributions: Small Earnings Exception: Special Groups: Boarders
From HM Revenue & Customs · National Insurance Manual
Any income from boarders which did not form a major part of the applicant’s income was disregarded as follows
when a boarder paid £20 or less for each week - all of the payment was disregarded
when a boarder paid more than £20 for each week - £20 plus half of any amount over £20 was disregarded