After outlining the present situation as far as British and European legislation are concerned and quoting previous legal decisions, Mr Howe comes to an interesting conclusion:
The Lisbon Treaty expands the EU's law-making powers and correspondingly restricts the power of the U.K. Parliament to make law. So the U.K. Parliament, while under the transient majority control of one party, has apparently permanently restricted the law-making power of future Parliaments, by ratifying the Lisbon Treaty. This restriction on the future law-making power of Parliament has no political legitimacy because it was never put to the British people for their approval.A law of this kind, if passed and actually applied, unlike the posturing of the German Karlsruhe Court, could have serious consequences in the UK and the EU. Is the Boy-King going to announce it as part of the Conservative manifesto?
According to orthodox and accepted understanding of the U.K.'s unwritten constitution, Parliament had no power to do this. As a matter of the U.K.'s internal law, Parliament can disregard or disapply any laws of EU origin even if that step might put the U.K. in breach of its international treaty obligations.
British courts have commented on this issue a few times since the U.K. joined what was called the Common Market in 1973. They have expressed the view that the U.K. Parliament retains the power to override EU laws if it expressly decides to do so, but if it is silent on the matter there is a presumption that normal Acts of Parliament will give way to EU law.
But the U.K.'s rule of parliamentary sovereignty is not embodied in any formal constitutional text. Rather, it is the product of centuries of custom and practice. Its continued validity ultimately depends upon the willingness of the judges in the U.K.'s new Supreme Court to uphold and apply it. There is a risk that over time, as more and more powers accrete to the EU, our judges might revise or depart from our long established rule of sovereignty.
This is why the U.K. now needs a bill which will write formally into law the rule that Parliament is sovereign and that it can, if it so chooses, over-ride any laws of external origin including those originating from the EU. This bill will cement the rule of sovereignty firmly into a formal constitutional text and make it resistant to erosion.