If the central purpose of Brexit is to restore the supremacy of Parliament, we should congratulate Labour for forcing a debate on the proposed terms of withdrawal. Let us demand that MPs should have a vote as well.

Brexit belongs to no faction. The referendum was not an election where the winner takes all. The circumstances are entirely sui generis and extremely delicate.

Both Scotland and Northern Ireland voted to remain, and the constitutional implications of this have yet to be confronted. A great majority of those below the age of thirty opposed Brexit, and many feel betrayed. It amounts to an inter-generational crisis.

The exact contours of Brexit were never defined. There was no Manifesto. The binary ballot presented to us on June 23 - nolens volens - contained not a single word about immigration. Many who voted to leave the EU want a liberal, amicable, open settlement with Europe.

It is the proper role of Parliament to discern the national will, and to impose its verdict on ministers. Theresa May is well-advised to bow to this imperative before Article 50 is triggered, even if raucous wrangling in the House greatly complicates negotiating tactics with Brussels.