Theresa May faces a chaotic and extreme Labour Party opposite her; has subdued and bewildered Conservative critics behind her, and is enjoying a honeymoon with the voters.  She could therefore have got away with not announcing anything of consequence about Brexit at the Tory conference which opens today, other than repeating her dogged mantra that it means itself.

However, we have an announcement – which is that Brexit also means a repeal bill or, as May and David Davis are styling it, a Great Repeal Bill, which will at once scrap the European Communities Act of 1972, thus making Britain a self-governing country once again, while also transposing EU law into British law “wherever practical”.

That second measure is intended to “ensure continuity”, and was recommended recently on this site by Peter Lilley, who is not exactly a catspaw of Brussels.  As he wrote, doing so will “provide businesses with certainty: they will be able to run themselves in the same way the day after Brexit as before; mean that Parliament can amend, repeal or improve any law subsequently; [and] ease the Parliamentary passage of leaving legislation by depriving die-hard Remainers of excuses to oppose it”.

The suggestion that transposition may not always be practical indicates coming Parliamentary debate about when it might not be, and some MPs and peers will not like granting “powers for ministers to make some changes by secondary legislation” (though the 1972 Act did that too in any event).  But it is unlikely that the Commons will vote the repeal act down, though the Lords will doubtless delay it, or try to.  Labour MPs with constituencies in the north and midlands, where the referendum vote for Brexit was decisive, will be nervous of defying their constituents.  Ken Clarke will not vote for the bill, but he is leaving the Commons at the next election, and can afford to make such an act of open defiance.  Most of his pro-Remain Conservative colleagues are not and cannot, and many of them do not contest the referendum’s verdict in any event.  None the less, watch out for ingenious wrecking amendments.

In legal terms, repealing the 1972 Act isn’t necessary to restore self-government since, as Christopher Howarth has pointed out on this site, “after a legal Brexit the treaties to which the Act gives force will not bind the UK”.  And such a Brexit will come into effect two years after Article 50 is moved, unless all parties concerned agree to extend the process.  However, legal terms and political terms are not the same, and the Government cannot and should not simply tell Parliament, in effect, to go hang – especially given the slenderness of its majority.

May and David also say that the Scottish and Welsh governments will “have opportunities to have their say and we will look at any suggestions they put forward”.  The former especially won’t like the Bill: we can expect a mass of argument from the SNP about its legitimacy, or a supposed lack of it.

Mention of Article 50 raises an inevitable question.  The bill “is expected to be included in the next Parliamentary session”.  But we do not know when the article will be moved, and the bill is inextricably linked to that event.  So now that we have a repeal bill announced, we next need a date for Article 50 – and the Government’s timetable will then be evident.

At that point, pressure on the Government to set out its negotiating position will intensify – Soft Brexit, Hard Brexit, Full Brexit, or whatever variety of Brexit you please.  So by announcing that a repeal bill is coming, May has taken a decisive step along a road that is clearly signposted.  She cannot turn back without political ruin.  And there is no sign whatsoever that she wants to.