(1) Schedule 4 (amended by section 14 of the Act of 2017) to the Principal Act is amended by the substitution of the Parts set out in Schedule 3 for Parts 1 to 3 of Schedule 4.

(2) This section comes into operation -

(a) in so far as it relates to -

(i) jobseeker’s allowance (other than where payable in accordance with section 148A of the Principal Act), and

(ii) farm assist,

on 20 March 2019,

(b) in so far as it relates to supplementary welfare allowance, on 25 March 2019,

(c) in so far as it relates to disability allowance, on 27 March 2019,

(d) in so far as it relates to -

(i) one-parent family payment (other than where payable in respect of a widow, widower or surviving civil partner),

(ii) jobseeker’s allowance payable in accordance with section 148A of the Principal Act,