The UK could pull out of Europe-wide human rights laws within the next five years unless reforms are made, the Government's senior law officer has indicated.
Attorney General Jeremy Wright said he did not know whether the UK would still be a signatory to the European Convention on Human Rights at the end of the current parliament in 2020.
Justice Secretary Michael Gove has promised to set out this autumn the Government's proposals to scrap the Human Rights Act - which enshrines the convention in British law - and replace it with a British Bill of Rights.
Appearing before MPs, Mr Wright was asked whether he thought the UK would remain signed up to the convention at the end of the parliament.
"The honest answer to that is I don't know," he told MPs. "A lot depends on what new settlement we can reach with the European convention mechanism."
Appearing before the Justice Select Committee, Mr Wright insisted that the Government's respect for human rights did not solely depend on membership of the convention.
But he said repeated controversial rulings from judges at the European Court of Human Rights in Strasbourg meant that the status quo was "not sustainable".
"I don't think that there is anybody, including anybody in Government, who has a serious issue with the content of the convention," he said
"The convention is a document that I think encapsulates some of the most fundamental human rights that we would all support and wish to continue supporting.
"But I think it's the interpretation of that document by the court in Strasbourg that has caused us the problem. It is the interpretation of that document and the Strasbourg jurisprudence that goes with that interpretation that I think this Government would wish to challenge and to seek to alter in terms of its effect on this country.
"So a lot will depend on whether or not we can reach an accommodation with the Council of Europe which means that we can gain some greater freedom in terms of the way in which the human rights convention is interpreted by the Strasbourg court than we have at the moment."
He added: "The status quo - which is that we receive a number of judgments from Strasbourg which don't represent what we think is a realistic and sensible view of human rights applicable to this country - that status quo is not sustainable and we have to do something about it."
Mr Wright insisted that the UK's international reputation for upholding human rights would not be damaged if it left the convention.
"It isn't solely the maintenance of our membership of the European convention that demonstrates our adherence to the principles of human rights," he told MPs.
The Government's top legal adviser also defended the decision not to release details of the legal advice he gave over air strikes in Syria that killed two Britons.
Mr Wright said convention meant his guidance remained confidential to allow it to be "full and frank".
He told MPs: "It means that we can give clear and more straightforward legal advice without any thought of that advice later being disclosed to the world."
Practical reasons, such as evidence gathered from the intelligence agencies, also made it difficult to disclose, he said.
David Cameron told the Commons last week that two British citizens, Reyaad Khan and Ruhul Amin, who were fighting for Islamic State (IS) were killed in an RAF drone attack.
Mr Wright told the committee he had given permission for the fact he had given advice to be disclosed but that was because of the "exceptional circumstances".
He added: "You can take it that I agree wholeheartedly with the Government's legal position.
"It's not right that Parliament should be expected to decide on this without any indication at all on the basis on which the Government took action and that's why the Prime Minister made his statement on the first day back in Parliament last Monday.
"I supported him in what he said and I agreed with what he said but I think that is different to disclosing the detail of law officers' advice, which should be preserved so that good government can be maintained."
Mr Wright said there had to be an imminent threat for a strike to be justified and the action had to be necessary, proportionate and comply with international law.
"In all of those respects I was satisfied that this was a lawful action," he added.
Mr Wright refused to say if fresh advice for further strikes would need to be given on a case by case basis.
Kat Craig, legal director at human rights charity Reprieve, said: "It is alarming that the Attorney General does not feel the need to tell MPs or the public even the most broad details about the UK's kill policy.
"All we currently know, is that the Prime Minister thinks he can authorise the killing of anyone, anywhere, without any parliamentary or judicial oversight.
"The UK appears to be going down the US route of a counter-productive, secret drone war which does more harm than good. When even US generals are warning that the drone programme causes more problems than it solves, it beggars belief that the British Government is adopting the model in full. We need a real debate, and for that we need the Government to come clean about this policy."
Mr Wright rejected claims that the Crown Prosecution Service was on the brink of collapse but conceded that it was "under pressure", including from the increase in the number of sexual abuse cases.
He said: "It is true, of course, that the CPS is under pressure. It's under pressure partly because of the caseload mix."
Sexual offences, which are often more complex cases, have risen by 10% between 2010 and 2015, while burglary cases are down by 26% and robbery has dropped by 38%.
"But it isn't true, when you look at the statistics, that all is terrible," he added.
He told MPs that the CPS conviction rate was 80% on average across magistrates and crown courts.
"I don't think that the CPS is on the brink of collapse but neither do I think that the CPS has been without its challenges over the last few years and, frankly, will not be without its challenges for the next few years either.
"That's partly unrelated to money and more to do with the kind of cases they are now having to contend with."