Though the earlier Factortame had also referred to Parliament's voluntary acceptance of the supremacy of EU law, Thoburn put less stress on the jurisprudence of the ECJ and more on the domestic acceptance of such supremacy; Lord Justice Laws suggested there was a hierarchy of "constitutional statutes" that Parliament could only expressly repeal, and so were immune from implied repeal.
The Units of Measures Regulations 1994 was introduced on the basis of Sections 2(2) and (4) of the European Communities Act 1972, which authorised Ministers to pass secondary legislation to bring the UK into closer compliance with its then obligations under EU law.
Also, Colin Hunt sold fruit and vegetables in Hackney, displaying his prices by reference to imperial measures, and was convicted at Thames Magistrates' Court in June 2001.
Julian Harman, a greengrocer, and John Dove, a fishmonger, sold their goods by sole reference to imperial measures at Camelford market in Cornwall; they were both convicted in August 2001 at Bodmin Magistrates' Court.
Instead, he was contesting the terms of the market stall licence proposed by the legal authority which required metric measures to be used; Sutton Magistrates' Court had rejected his claim.
The appellants argued first that the fact that the kilogram and the pound were recognised as equally legal units – notwithstanding the 1994 modifications – operated as an implied repeal of Section 2(2) of the European Communities Act 1972 in respect of weights and measures regulation.
[citation needed] The second argument concerned the nature of the authorisation contained in the European Communities Act 1972, what is known as a Henry VIII clause delegating to the Executive a power to amend primary and secondary legislation to achieve a certain aim.
He also accepted that implied repeal could work pro tanto and that the Australian case relied upon by the appellants correctly stated the law of England.
"[7] In disposing of the second argument Laws took the opportunity to outline a constitutional framework within which the competing and seemingly irreconciliable principles of Parliamentary sovereignty and EU supremacy could be accommodated.
Laws wrote that the question of whether the European Communities Act was affected by implied repeal had already been determined by the House of Lords in Factortame.
[8] The reason for their ruling was: In the light of all the material in its possession, and in so far as the matters complained of were within its competence, the Court found that they did not disclose any appearance of a violation of the rights and freedoms set out in the convention or its protocols.In the event, because of later changes in EU and UK legislation, it continued to be lawful for traders to use imperial measures as "supplementary indications" alongside the required "primary" metric measures even after the end of 2009.