# European Union (Withdrawal) Act 2018, Paragraph 1

Extent: E+W+S+N.I.

(1) There is no right in domestic law on or after IP completion day to challenge any assimilated law on the basis that, immediately before IP completion day, an EU instrument was invalid.
(2) Sub-paragraph (1) does not apply so far as—
(a) the European Court has decided before IP completion day that the instrument is invalid, or
(b) the challenge is of a kind described, or provided for, in regulations made by a Minister of the Crown.
(3) Regulations under sub-paragraph (2)(b) may (among other things) provide for a challenge which would otherwise have been against an EU institution to be against a public authority in the United Kingdom.

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Source: https://www.legislation.gov.uk/ukpga/2018/16/schedule/1/paragraph/1 (the official version)
Page: https://openlegislation.uk/european-union-withdrawal-act-2018/schedule-1/paragraph-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.