Westminster The Mother of All Parliaments - sovereign once more? Photograph by author, all rights reserved.

"Take back control." This was the mantra which propelled the leave camp to victory in 2016 - the singular battlecry of Brexiteers across the land ahead of the historic referendum on our membership of the European Union. Simple and effective, it communicated in three short words the primary benefit of extricating ourselves from Brussels's grip - namely the restoration of the supremacy of our parliament at Westminster. Duly convinced by the argument that British laws should be made in London, not Brussels, and that our own government, not the European Commission, should have the final say on matters of state, the electorate promptly voted to leave.

We are all too familiar with what happened next. A spurned political establishment sought to hamper our exit. A weak Prime Minister gambled her majority and lost, before negotiating an appalling deal with her European counterparts. Seeing Brexit through proved a monumental struggle - it was not until January 2020 that the UK left the EU in name only, and not until December of the same year that Freedom of Movement and our membership of the Customs Union were brought to an end.

But the struggle was worth it. The supremacy of the British Parliament at Westminster has been duly reasserted and national sovereignty regained (outstanding issues in Northern Ireland excepted). Why, then, so soon after having reached the objective we had sought, has the government agreed to surrender our sovereignty again - only this time to the United States in the form of a global minimum corporate tax rate?

This is exactly what G7 Nations (the UK among them) have today agreed in principle. As Matt Kilkoyne of the Adam Smith Institute rather bluntly put it, "in doing so the UK Government has signed away the sovereign right of Parliament to set taxes for the British people - and the rights of the Overseas Territories and Crown Dependencies to set their own fiscal policy.*" Coming so soon after the end of the Brexit transition period, the enthusiasm with which the Government has thrown away our right and ability not only to set corporate tax as we see fit, but use it as a method of enhancing our global competitiveness and promoting economic growth comes as a blow so cruel that you might be excused for calling into question the Government's commitment to exploiting the benefits of our departure at all.

For what it is worth, there is little chance that the current UK Government would seek to lower corporate tax below 15% (apparently the new agreed minimum rate) in either the short or medium term (in fact, the Chancellor only recently announced an ill-advised hike from 19 to 25%, effective 1st April 2023, putting "tax and spend" firmly back on the agenda moving forward) but this is rather beside the point. If a future Chancellor decided to slash the rate of corporate tax to 10%, that should be his prerogative. He would, of course, have to explain his decision to the public and submit to our verdict at the ballot box, but that is exactly the way it should be in a democratic nation state. It is our business and no one else's. Tax policy should be determined domestically, in our own national interest - not at the behest of any foreign leader.

If other countries wish to impose an additional corporate tax burden in future, then they must accept that doing so would hamper their global competitiveness. That would be their problem to face, not ours, and no leader should expect or demand that other major economies adjust their corporate tax rates to compensate for their own reduced competitiveness.

In leaving the European Union, we sought to return full control of British affairs to Westminster. It was for this fundamental principle that campaigners struggled in the long years following the 2016 referendum. In light of this struggle, it was deeply unwise for the Treasury to consider restricting our domestic policymaking latitude and hobble our global competitiveness at Washington's command - and more foolish yet for the Chancellor to have agreed to it. To acquiesce to the imposition of a global corporate tax rate is to bind our hands once again and surrender a hard-won principle. It makes a mockery of the notion that we have taken back control.

*https://twitter.com/ASI/status/1401140390489694215