Anger at the way republican terrorism suspects from Northern Ireland were issued with letters by the Government telling them they were not sought by police is understandable and justified.

Some 190 so-called on the runs (OTRs) received letters from the Northern Ireland Office allowing them to return to the UK under a scheme launched by the Labour Government of Tony Blair. Sinn Fein gave the Government a list of names and, in each case, the name was checked by the Police Service of Northern Ireland (PSNI) to see if there was enough evidence to lead to a prosecution against that individual. If there was not enough evidence, one of the letters was issued. But the missives did not remove the risk of future prosecutions if further evidence were to emerge.

That detail has been crucial, since the letters have been widely interpreted by critics as amounting to an amnesty for the OTRs. The Government insists they were not and have had that confirmed by Lady Justice Hallett, who has reviewed the way the scheme operated.

However, the scheme was still badly flawed and administered secretively; or as the judge put it "not widely publicised".

And in the case of one terror suspect, John Downey, who was wanted for the Hyde Park Bombing of 1982 in which four soldiers died, the fact that he had received a letter which contained an erroneous statement due to a "catastrophic mistake" by the Northern Ireland police, led to the collapse of the prosecution case against him when the judge accepted there had been an "abuse of process".The review found that the scheme lacked proper lines of accountability and safeguards and that, when mistakes were made, opportunities to rectify them were missed.

The scheme has been halted but concerns still remain about mistakes identified in the review relating to two other individuals sent the letters in error and whether that could undermine future attempts at prosecuting them (though that is less likely than in the Downey case since steps have been made to rectify the errors in those two cases). The First Minister of Northern Ireland, Peter Robinson, has called on the Northern Ireland Secretary Theresa Villiers to ensure no-one could use the letters in the future to avoid questioning or prosecution, and this assurance is indeed essential.

Central to the whole controversy has been the "below the radar" nature of the scheme; many politicians in Northern Ireland had no idea it existed. With thousands of bereaved families still waiting for justice, this secretiveness will only raise fears that the guilty could be getting undue protection so as not to rock the boat of the peace process. Since the Good Friday Agreement, Northern Ireland has been on the road to prosperity and lasting peace. Compromises have inevitably had to be made but such compromises have to be carefully managed and have the agreement, however reluctantly, of all parties. This deal failed those tests and as a consequence, has caused more harm than good.