(1) Rule 1 of Part 2 of Schedule 3 to the Principal Act is amended by substituting the following paragraph for paragraph (9) (amended by section 10 of the Act of 2011):

"(9) in the case of -

(a) a fisherman, the gross income derived from any form of self-employment, or

(b) a farmer entitled to or in receipt of farm assist, the gross yearly income which the farmer or his or her spouse, civil partner or cohabitant may reasonably be expected to receive from farming or any other form of self-employment,

less any expenses necessarily incurred in carrying on any form of self-employment;".

(2) This section comes into operation on 3 April 2013.