The Historical Enquiries Team set up to investigate around 3,200 unsolved killings has run up a bill of £34m so far and could rise to £45m, some 60% more than the original budget. When statutory inquiries such as the Saville Inquiry into Bloody Sunday are taken into account the bill amounts to £350m and is still running.

Probably the most astonishing fact to emerge from the MPs' deliberations is that of the 1,100 old cases opened by the HET, only one case has been passed to the Public Prosecution Service for possible court action.

While there is every sympathy with the relatives of people murdered during the three decades of the Troubles and their desire to find out who killed their loved ones and why, it has to be accepted that, to date, the return for the investment in re-opening those cases has been minimal.

Looked at logically, trying to find out who was responsible for killings dating back to the early 1970s is a mammoth task and a challenge faced in few other places in the world.

There are bound to be problems with evidence — was it destroyed or contaminated over the intervening years — and with witnesses who may have died or whose recollections are now hazy. As well, the perpetrators of the killings themselves may now be dead.

However unpalatable it may be to relatives who still seek justice, the bald fact is that they are unlikely to get it, even with the best intentions of all concerned. Even if killers were brought to court now, it is unlikely they would serve any time behind bars.

Statutory enquiries present a different challenge as their costs are almost entirely due to legal fees. There does not seem any way of conducting public tribunals without huge, and to some people, excessive, costs.

We only have to look to Dublin to see the enormous expense of the seemingly endless tribunals in that jurisdiction. However, having set up the statutory enquiries, there now seems little option but to continue with them until they reach their conclusion.

A different approach may need to be taken to the HET investigations.

Not only are they consuming a large amount of public money but also the time and input of key PSNI staff. That is diverting them from their primary role of policing Northern Ireland today.

It will be the supreme irony if investigations into past crimes were to allow today's criminals, including dissident terrorists, to operate with impunity. We do not want to create a new generation of disenchanted victims.

The First and Deputy First Ministers, Peter Robinson and Martin McGuinness, should examine this problem as a matter of urgency.

There are a plethora of enquiries and bodies charged with examining the past. Sadly, history cannot be unwritten, but are we in danger of becoming obsessed with the past to the detriment of the present?