Tomorrow, the House of Commons will debate whether to transpose the EU’s Charter of Fundamental Rights into UK law after Brexit. The Government’s European Union (Withdrawal) Bill proposes not to transpose it, while a number of opposition MPs, and some rebels on the government backbenches, have tabled amendments proposing that it be retained as part of UK domestic law. In our Lawyers for Britain paper, The Charter of Fundamental Rights in UK law after Brexit: Why the Charter should not be transposed, we argue that the Government is right to deny the Charter a place in UK law after exit. Citizens agree to be ruled by law because it rules our society – and its institutions – in a way that is predictable and certain: the Charter is neither certain nor predictable in its operation, and so must be rejected if the UK is serious about preserving the proper rule of law. The Charter, if retained, would overlap with our existing human rights regimes – the European Convention on Human Rights (as incorporated by the Human Rights Act 1998), which the Charter substantially duplicates but can also exceed, and the common law. As the Human Rights Act and the common law will regulate the body of retained EU law, it is difficult to see what extra value the Charter would add (apart from all the extra, possibly lucrative work for lawyers) that would justify the price to be paid in retaining it. That cost would be high: in terms of legal certainty, as discussed below, but also in terms of ease and clarity – both for litigants seeking to defend their rights, and for administrators and lawmakers ensuring decisions and laws are rights-compliant. To borrow a comparison used by Lord Pannick in the Gina Miller case, it would be a curious state of affairs indeed if there were more authoritative clarity about the restrictions on dangerous dogs than about the citizen’s fundamental rights against the state. The Charter had an uneasy passage into UK law. Originally meant to form part of the abortive ‘European Constitution’, it acquired binding legal force in the EU with the 2009 Lisbon Treaty. Its explicit purpose was to restate the fundamental rights already recognised by EU law. The UK – along with Poland – believed, with good reason, that the Charter would widen the scope for EU law to override national law, and so both countries secured what they thought was an opt-out, in the form of Protocol 30 of the Lisbon Treaty on the Charter. The European Court of Justice thought differently, alas, and ruled in 2013 that the ‘opt-out’ was in fact no opt-out at all: the Charter applies in the UK and Poland just as it does in all other EU member states. The EU Withdrawal Bill gives the UK Parliament a second chance to remove the Charter from UK law. Here’s why it should seize that second chance. The Withdrawal Bill aims, sensibly, to keep EU law on the statute books after Brexit so that businesses and individuals can be sure that their rights and obligations remain the same – pulling the rug from under our feet is in no one’s interests. Retaining the Charter could not, however, serve the purpose of maintaining legal certainty. It protects rights by operating in tandem with the doctrine of the primacy of EU law, which will continue to apply to EU law incorporated prior to Brexit: this means that any EU or UK law, or a provision within it, already on the statute books could be disapplied – essentially switched off – if it were incompatible with the ECJ’s interpretation of Charter rights. If we cannot say with certainty when Parliament’s laws will be supreme, including the laws transposed by the Withdrawal Bill, then the UK’s standard of legal certainty will not be preserved. One might counter this by saying that we are used to EU law carrying a big stick, and retained EU law will continue to do so after Brexit. True enough. But the operation of the Charter makes it even more difficult to predict where the big stick might fall – such that retaining the Charter would really mean, to change metaphor, sowing the statute book with hidden landmines. Take the recent case of Janah v Libya; Benkharbouche v Embassy of the Republic of Sudan, which was brought by two embassy workers relying on the EU-derived Working Time Regulations. The UK Supreme Court held that provisions of the State Immunity Act 1978, which grant the diplomatic missions of foreign states immunity from civil actions, are incompatible with the Charter on the ground that they denied the two workers the right to bring their employment claim before the courts. Whenever a member state implements an EU law, as in this case, the Charter springs open like an umbrella – that implementation must then respect the full range of rights opened up by the Charter, any one of which will knock down any national law standing in its way. It is clearly a very good thing for people to have the right to access the courts. But even a good law is marred if it is wayward and unpredictable in its operation. It could not have been predicted that the Charter would allow the Working Time Regulations to obstruct the UK’s development of the international law surrounding state immunity, nor that it might endanger the immunities of British diplomats operating in other countries which will be able to point to the sweeping away of accepted diplomatic immunities by the UK courts as an excuse for possibly more damaging actions against UK diplomats. One could predict with greater certainty, however, that such a capricious mechanism for protecting rights would not enhance the standing of human rights law among the public – surely a self-defeating result for the Charter’s supporters. Most importantly, supporters of the Charter cannot now predict with any certainty what its intended scope of future operation would be, for the simple reason that it is unforeseeable. Proposers of the amendment offer an open-ended commitment: Parliament should agree to relinquish its laws whenever, from time to time, the Charter, as interpreted by the ECJ, so demands. An open-ended commitment to the legal order that the UK is leaving is not compatible with new-found sovereignty, and constitutes a timid failure to reap its benefits. Even if, after full and proper debate, the UK were to come round to the idea of a strong rights charter with the power to override Parliament, an instrument like the Charter, with so many inscrutable avenues leading to judicial strike-down, could not be suitable. If Parliament can be overridden, citizens, decision-makers and legislators need a clearer idea of when that can happen. The purpose of the Charter of Fundamental Rights is to state and enforce the fundamental rights that unite the member states of the EU as they move towards ever closer union. That purpose cannot apply to the UK after Brexit. Nor could the future relationship with our European neighbours, based on trade and cooperation, reasonably require convergence on fundamental rights, any more than a future trade agreement with the USA would reasonably require us to adopt the right to bear arms. If citizens and lawmakers in the UK decide subsequently that a new rights regime is needed, then it should be one founded upon that purpose, tested in public debate, and consented to by those whom it protects and by those against whom it would be applied.