The government's bill to exempt British soldiers from prosecution for crimes including torture and genocide is unjustifiable, will not even achieve its aims, and violates international law, a parliamentary committee has said.
The cross-party human rights committee, which includes MPs and peers from all the main parties, said the Overseas Operations Bill would also be ineffective at protecting British troops from vexatious prosecution.
Harriet Harman, who chairs the group, said members of the armed forces were "not above the law" and "nor should they be exempt from upholding human rights".
She argued that there were "very troubling issues" with the bill", which human rights groups and some senior military figures have said will undermine the UK's reputation abroad.
"I don't think it's the drafting of the bill that's the problem, the bill is perfectly drafted according to the policy. The problem is the policy," the MP, who is also a QC, told journalists ahead of the release of the committee's report.
Ms Harman said defence minister Johnny Mercer had been unable to tell her committee of any vexatious prosecution that should and would have been stopped by the bill's provisions - which would create a legal presumption against prosecution for offences that are more than five years old.
The proposed law would also impose a shorter and more inflexible limitation period for human rights violations, and impose a duty to consider opting out of the European Convention on Human Rights for future military operations.
Defence Secretary Ben Wallace says the bill will end "the vexatious hounding of veterans and our armed forces by ambulance-chasing lawyers motivated not by the search for justice, but by their own crude financial enrichment".
But the MPs' report says the bill "does nothing to address the issue of repeated investigations".
"Instead the Government is effectively using the existence of inadequate investigations as a reason to legislate to bring in further barriers to bringing prosecutions or to providing justice for victims. It is therefore difficult to reconcile the contents of the Bill with either its stated objective or the underlying issues," they warn.
"No problem has been identified of excessive or unjust decisions to prosecute members of the UK Armed Forces. We can therefore see no justification for introducing the statutory presumption against prosecution."
The committee report says the MPs and peers have "significant concerns that the presumption against prosecution breaches the UKâs legal obligations under international humanitarian law, international human rights law and international criminal law".
They says the bill risks contravening the UKâs obligations under the UN Convention Against Torture, the Geneva Conventions, the Rome Statute and international customary law.
"At a minimum, the presumption against prosecution should be amended so that it does not apply to torture, war crimes, crimes against humanity or genocide," they say.
Ms Harman said she had no issue with addressing this problem, but that the proposed policy would not achieve it.
"I think it's quite out on its own in bringing forward legal changes that go so side of the mark in what it is that it's purporting to attempt to do," she said.
"I think that that's very exceptional for there to be a clear argument about what the problem is, and then a bit to be brought forward in the name of that that does absolutely nothing to deal with that, but deals with something completely different in a way that is bad."
Labour leader Keir Starmer whipped to abstain on the bill in September, sacking left-wing MP Nadia Whittome as she joined 76 other MPs, including 17 other Labour rebels, in voting against it. It was also opposed by the SNP and Liberal Democrats.
Other groups and figures to criticise the bill include Amnesty International UK says the plan would case âreal and lasting damage to the reputation of the Armed Forcesâ, while Conservative MP and former cabinet minister David Davis has said he is âdeeply troubled by government plans to decriminalise torture by British personnelâ.
General Sir Nick Parker, former commander of British land forces, is the most senior military figure to have spoken out against the bill. He said the UK "shouldnât be treating our people as if they have special protection from prosecution" and that it was vital for British soldiers to be seen be operating within the law.