More concerning would be a withdrawal from the ECHR, which focuses on fundamental human rights per se, not fundamental rights arising out of EU membership.
Both are concerning, though. I was recently educated by a real lawyer about my idealistic view of the ECHR. It turns out that I had a fundamental misunderstanding for years, so I will share the essence of what they told me in case I wasn't the only one. (I am not a lawyer, so please forgive any continuing misunderstandings in what follows.)
The thing about the ECHR is that it doesn't really operate as a law, more a benchmark against which other laws are measured. A UK court will attempt to interpret UK law in a way that is compatible with the ECHR/HRA where possible. However, if a law cannot be so interpreted and is not compatible with the ECHR, the most a court can actually do is issue a declaration of incompatibility, which is the political equivalent of being told off and put in the naughty corner. The law itself still stands. Usually after a declaration of incompatibility the government does acquiesce and modify the law to be more compatible, but there have been some notable instances such as voting rights for prisoners where they have refused to do so. At that point, regardless of any theoretical protections afforded by the ECHR, the practicality is that is has no more power.
The legal situation seems to be quite different as far as the Charter and enforcement through the CJEU go, because that mechanism appears to have real legal teeth in its own right. This is the mechanism that will almost certainly disappear as part of Brexit, and so it is important for the protection of rights and liberties that something analogous be enshrined in primary UK legislation. The government of the day could still change it later, because in this country we don't have a constitution that guarantees these sorts of rights and sits at a higher level of law, but at least they would have to do so actively and under full parliamentary scrutiny like any other law.
This is more or less true, but what the ECHR/HRA does is place a very strong presumption at the heart of UK law that the government of the day will not seek to violate the rights granted under the ECHR. In practice, this means the courts will go to great lengths to interpret the law in line with them, even if it involving reading them in ways that is not readily apparent solely from the text of the Act, before resorting to a declaration of incompatibility. Per the House of Lords:
> In accordance with the will of Parliament as reflected in [the HRA] it will sometimes be necessary to adopt an interpretation which linguistically may appear strained. The techniques to be used will not only involve the reading down of express language in a statute but also the implication of provisions. A declaration of incompatibility is a measure of last resort. [2001] UKHL 25 at 44
You can see similar in R. vs Lambert [2001] UKHL 37 (e.g. at 42). The Court was willing to read a requirement that that the defence must prove a defence as merely requiring that the defence provide sufficient evidence to that effect.
It also provides a degree of political scrutiny - few governments are going to want the courts declaring that they are failing in their human rights obligations, and so even if it does not prevent them from doing so, it provides a very strong incentive to not do so.
This is analogous to judgements made through the ECJ - they only have more legal teeth because A) Parliament has (by the EU treaties) granted them presumed superiority to UK law and B) the EU can take direct actions against the UK because they are a Member State. For the former, there is very little, legally speaking, to prevent the UK government from overriding that presumption and acting counter to their EU obligations (much as it is possible to deliberately set aside the HRA):
> If the time should come when our Parliament deliberately passes an Act with the intention of repudiating the Treaty or any provision in it or intentionally of acting inconsistently with it and says so in express terms then I should have thought that it would be the duty of our courts to follow the statute of our Parliament. Macarthys Ltd v Smith [1980] ECR 1275
Further, that presumption, nor the ability of the EU to take direct actions against the UK, will not continue to exist should the UK continue with leaving the EU. Even if the Charter were retained, the main method of action would be political, rather than having direct effect on UK law and the UK courts. If anything, its scope of action will be less than the ECHR, because it does not an Act analogous to the HRA enabling the courts to make strained re-interpretations of UK law to comply. There would likely also be no ability for British citizens to take cases to the ECJ (which they can do with the ECtHR), so there would be limited external guidance and oversight as to how the rights should apply to the UK context.
IMO, a Bill of Rights would be strictly worse than what is already provided for under the HRA. Because Parliament is sovereign, it is no more immune to the whims of the future governments than the HRA already is. In some ways, directly enumerating rights in UK law may make it slightly _more_ vulnerable - if a future Act of Parliament contradicts one of the rights, the doctrine of implied repeal may apply (the newer Act overwrites the older) and nullify that right. Because the HRA incorporates by reference, and the UK has international obligations they have agreed to regarding them, it is easier for the courts to argue that it cannot have been the will of Parliament to remove rights en masse or act outside the bounds of their international obligations, and interpret the Act in that light. They would be able to require that future Acts must _explicitly_ set aside the rights, much as they have done with EU laws by reference to Treaty obligations (see Macarthys above, or the Factortame series of cases).
In addition, there would be no source of external oversight. Even if the ECtHR is somewhat toothless, it provides external guidance as to how the rights should be utilised, which the UK courts can then apply in their own interpretations. You cannot get that additional layer solely through the application of UK law.
(FWIW - studied law a few years ago, with a focus on human rights/EU law, but never practiced so some of the details/nuances may be lost)
Just to be clear, I wasn't advocating the loss of the ECHR/HRA benefits, merely that anything currently protected by the Charter and EUCJ should be established in primary legislation here as well, so that post-Brexit our own courts can take it into account directly.
My personal view is that parliamentary sovereignty is a dubious principle at best in this sort of situation, and that we are long overdue for constitutional reform such that the protection of fundamental rights is enshrined in a higher law and interpreted by a higher court over which even the government of the day does not have supremacy. Unfortunately, rather like reform of our blatantly broken electoral system, there seems little prospect of that any time soon, and so trying to protect those rights and freedoms as well as we practically can under our existing system may be the best we can do for now.
Both are concerning, though. I was recently educated by a real lawyer about my idealistic view of the ECHR. It turns out that I had a fundamental misunderstanding for years, so I will share the essence of what they told me in case I wasn't the only one. (I am not a lawyer, so please forgive any continuing misunderstandings in what follows.)
The thing about the ECHR is that it doesn't really operate as a law, more a benchmark against which other laws are measured. A UK court will attempt to interpret UK law in a way that is compatible with the ECHR/HRA where possible. However, if a law cannot be so interpreted and is not compatible with the ECHR, the most a court can actually do is issue a declaration of incompatibility, which is the political equivalent of being told off and put in the naughty corner. The law itself still stands. Usually after a declaration of incompatibility the government does acquiesce and modify the law to be more compatible, but there have been some notable instances such as voting rights for prisoners where they have refused to do so. At that point, regardless of any theoretical protections afforded by the ECHR, the practicality is that is has no more power.
The legal situation seems to be quite different as far as the Charter and enforcement through the CJEU go, because that mechanism appears to have real legal teeth in its own right. This is the mechanism that will almost certainly disappear as part of Brexit, and so it is important for the protection of rights and liberties that something analogous be enshrined in primary UK legislation. The government of the day could still change it later, because in this country we don't have a constitution that guarantees these sorts of rights and sits at a higher level of law, but at least they would have to do so actively and under full parliamentary scrutiny like any other law.