Relatives of people killed during the Northern Ireland Troubles have condemned the government’s plan to end all criminal prosecutions as a death knell to their hopes for justice and accountability.

Families from all sides of the conflict expressed anger and hurt on Wednesday at what they said was an effective amnesty for perpetrators.

“We’re seeing de facto impunity,” said Mark Thompson, whose brother Peter was shot dead by British soldiers in Belfast in 1990. “This is a government that doesn’t care a jot for human rights and the rule of law.”

Relatives who lost family members to republican and loyalist paramilitaries said Boris Johnson’s government was extinguishing any slender hopes of one day seeing terrorist killers behind bars.

“Tell me, prime minister, if one of your loved ones was blown up beyond recognition, where you were only able to identify your son or daughter by their fingernails because their face had been burned so severely from the blast and little of their remains were left intact, would you be so quick to agree to such obscene legislation being implemented?” said Julie Hambleton, whose sister Maxine was one of 21 people killed when the IRA bombed pubs in Birmingham in 1974.

The Northern Ireland secretary, Brandon Lewis, unveiled the plan to deal with so-called legacy cases to the Commons. It proposes a statute of limitations that would end all prosecutions in Troubles-related cases pre-dating the 1998 Good Friday agreement.

Brandon Lewis: Troubles amnesty plan is best chance of 'some sense of justice' – video
Brandon Lewis: Troubles amnesty plan is best chance of ‘some sense of justice’ – video

The government’s aim is to shield army and other security force veterans from what it considers vexatious prosecutions. That requires extending the same protection to former paramilitaries.

Johnson was sacrificing bereaved families for his own political interest, said Shane Laverty, whose brother Robert, an 18-year-old police constable, was shot dead in 1972.

“He’s separating the idea of law and order with a pen. He doesn’t care what the people in Northern Ireland think and we are left to pick up the pieces. It creates a group of people who feel very disenfranchised and have nowhere to go.”

Of approximately 3,600 killings during the conflict, which started in 1969, more than 3,000 remain unsolved. The cold case backlog has tangled policing and politics and produced just a handful of prosecutions.

Thompson, who heads the group Relatives for Justice, said the government was junking the 2014 Stormont House agreement, which charted a path to truth and reconciliation, to protect the security forces. “We were lectured in the conflict about the rule of law. Now we see the very opposite happen when they’re the ones in the dock.”

Earlier this month, prosecutors halted the trial of Soldier F, who is accused of two murders during the Bloody Sunday shootings in Derry, saying the test for prosecution was no longer met. A legal challenge to that decision is likely to be overtaken by the government’s plan.

The statute of limitations is not expected to apply to killings committed after the Good Friday agreement, which was signed on 10 April 1998.

A dissident IRA bomb killed 29 people in Omagh four months later, leaving the perpetrators open to prosecution. Claire Monteith, who lost her 16-year-old brother Alan in the atrocity, said the government’s plan created two tiers of victims either side of the calendar.

“It’s a knife in the heart for all of us. Victims and survivors are exhausted trying to get truth and justice,” she said.