Attempts by defence ministers to limit torture prosecutions against british troops are an international embarrassment that risk harming the uks reputation for upholding humanitarian law, former military chiefs and senior lawyers have warned.

The overseas operations bill which is due to come before parliament for a second reading on wednesday seeks to curb historical claims against uk soldiers who have been operating in foreign theatres such as iraq and afghanistan. one of its proposals is for prosecutionsof torture and other serious crimes to be made within five years. only charges relating to rape and sexual violence are exempt from the cut-off.

Opponents of the bill fear the time limit creates a de facto immunity for service personnel facing allegations of war crimes. it could also put the uk at risk of violating international agreements it is party to, such as the un convention against torture.

General sir nick parker, a former commander of british land forces, said he was particularly concerned about creating a two-tier justice system, in which troops are treated differently to civilians. we shouldnt be treating our people as if they have special protection from prosecution, he told the financial times. what we need to do is to investigate properly so that the ones who deserve to be prosecuted, are.

The former commander also urged ministers not to damage the reputation of the british armed forces overseas, saying that in the midst of a military operation, it was vital to be seen to be operating within the bounds of the law. anything which might even cause people to question that should, in my view, be treated with great care, he said.

Bruce houlder qc, who served as director of service prosecutions from 2008 to 2013, said that if the five-year limit on prosecutionswas brought in, it would be an international embarrassment.

We have been held up as a country which abides by the rule of law...so the idea that we then treat torture and other grave crimes including homicide as excusable, and legislate in effect to make it difficult in the extreme to prosecute after five years, is really outrageous, he said.

Mr houlder added that if the uk was failing to prosecute war crimes due to a statute of limitations, the international criminal court could still pursue claims against british troops.

Lord guthrie, former chief of the defence staff, malcolm rifkind, former defence secretary, and dominic grieve, former attorney-general, have all expressed reservations about the legislation, which lord guthrie said would let torturers off the hook. last year senior pentagon officials warned us president donald trump against granting pardons to american troops accused of war crimes over fears this would undermine the military justice system.

The ministry of defence argues that the wars in iraq and afghanistan spawned an unscrupulous claims industry, which offered financial incentives to make allegations against service personnel.

The most notorious controversy involved phil shiner, a solicitor who was struck off in 2016 for multiple professional misconduct charges while bringing false iraqi compensation claims against the british army.

About 70 per cent of allegations received by the independent iraq historic allegations team, which investigated allegations of abuse of iraqi civilians by uk armed forces personnel, were dismissed as having no case to answer, according to the mod, which pointed out that false allegations have cast a shadow over the lives of innocent personnel.

This legislation is not about providing an amnesty or putting troops above the law but protecting them from lawyers intent on rewriting history to line their own pockets, said defence minister johnny mercer on tuesday. it will put an end to lawfare and make sure personnel and veterans are not repeatedly and indefinitely called upon to give evidence about events that happened years ago.

The bill applies only to overseas operations, so excludes incidents relating to northern ireland.