Six former detainees are suing the Ministry of Defence, the secretary of state and the police on the 40th anniversary of internment.
Writs were delivered at Stormont on Tuesday morning.
In the early hours of 9 August 1971, dozens of people were rounded up in Northern Ireland by security forces in an attempt to bring an end to violence.
Three hundred and forty-two people, suspected by the police of being in the IRA, were detained without trial.
The former internees are also suing the estate of the late Brain Faulkner, the former Northern Ireland prime minister who first ordered internment.
Solicitor Padraig O Muirigh, who is representing the six men, said a document from 1974 recording a meeting of the Northern Ireland Office, but which included the attorney general, the Home Office and the Ministry of Defence, showed the policy to be discriminatory against Catholics.
“These papers demonstrate not only the existence of a discriminatory policy against the nationalist community,” he said.
“But also the indiscriminate nature of the arrests by the Army, who were clearly instructed to arrest without question those in a household over the age of 18 in circumstances where there was uncertainty over the identity of the person being sought out by the Army.”
Despite being launched to quell violence, the Troubles only intensified – 17 people were killed in the next 48 hours and there was rioting in nationalist areas.
More than 100 others on the list to be interned were able to flee and escape the raids.
9 August 1971: Operation Demetrius – internment without trial introduced for terrorist suspects – launched
342 men picked up in initial raids, but violence only intensifies
A total of 1,981 people interned while policy lasts
December 1975: Internment ended by British government, last 75 detainees released
Of the 342 people arrested in the first day of internment, 104 were released within 48 hours.
The policy was ended in December 1975 by then Secretary of State Merlyn Rees and the final 75 detainees released.
The majority of internees – 1,874 – were nationalists, but more than 100 were loyalists.
Many claimed they had no connection to paramilitary organisations and some of the intelligence used to identify suspects is believed to have been badly out of date.
Conservative MP Patrick Mercer, who served as a soldier in Northern Ireland, said he believed internment only made things worse.
“To quote my company commander at the time when I arrived in 1975, he said ‘if we hadn’t have introduced internment three or four years ago I reckon we’d have gone home a long time ago,'” Mr Mercer said.
“I think it stoked the conflict up for at least the next 10 years, if not 20.”
Sinn Fein assembly member Fra McCann welcomed the decision by the former internees to take a court case.
“As a former internee I have firsthand experience of what the men and women who were arrested went through,” he said.
“Many of the people interned still suffer the traumatic effects of that period yet have never been issued with as much as an apology even though the British government recognised that many of the people arrested were innocent.
“I welcome the decision today to serve papers on the British MoD, RUC, British secretary of state and the estate of the late Brian Faulkner (former unionist prime NI minister) and I am fully supportive of it.”