Twenty families of those killed by the British army in Northern Ireland between 1971 and 1992 are to sue PSNI chief constable Matt Baggott over the manner in which the cases have been re-examined.

Margaret Kennedy, whose mother was shot dead on the Falls Road in west Belfast in October 1971 is taking the lead case.

The families are angry at the way in which the Historical Enquiries Team (HET) has investigated unsolved murder cases. The team, a separate unit within the PSNI, was set up in 2005 to re-examine more than 3,000 murder cases which have never been closed.

However Ms Kennedy has said the investigation carried out by the team has left her relatives re-traumatised, distressed and still without any form of closure.

“After eight years engagement with the HET it is clear that there is still one law for the military and another law for everyone else,” she said.

Her Majesty’s Inspectorate of Constabulary , the British police watchdog, recently criticised the team, claiming “the approach to state involvement cases is illegal and untenable as it is inconsistent with UK Article 2 European Convention on Human Rights obligations”.

The families’ solicitor, Kevin Winters, said today the Historical Enquiries Team was put centre stage by the UK government as its response to serious criticisms by the ECHR but has failed to meet the most basic of obligations. That in turn leaves families with little choice but to seek redress through the courts in search of accountability and force the changes that are long overdue.”