The European Communities Act 1972 (ECA) was the domestic UK legislation that bound the UK to membership of the EC (now the EU) with effect from 1st January 1973 and provided for EU treaties and rules to have local application within the UK as part of UK law.
The European Union (Withdrawal) Act 2018 (EUWA) provided in section 1 for the repeal of ECA with effect from "exit day" (currently, 11pm UK time on 31st October 2019) but section 1 itself had not been brought into force - until 18 August 2019 when the European Union ( Withdrawal) Act 2018 (Commencement No.4) Regulations 2019 (SI 2019/1198) (the regulations) were signed into law by the Brexit Secretary , Steve Barclay.
The regulations brought section 1 of EUWA into force with the effect that the ECA will be automatically repealed on exit day. However, the story is not over yet because "exit day" could itself change - it has done so twice already - depending on whether or not a further extension is sought to the Article 50 withdrawal notice period.
The regulations are a technical requirement to get the Brexit show on the road. Steve Barclay has, however, underlined their symbolic significance by a burst of purple prose in the announcement which accompanied the passing of the regulations, stating that "this is a landmark moment in taking back control of our laws from Brussels".
The intricacies of the legal process towards Brexit may generally only be of interest to lawyers and politicians but are vital building blocks in a rules- based society.
Whilst not everybody would share the Brexit Secretary's excitement at the passing of the regulations, it is nevertheless a significant legal step along the Brexit highway.