Mr Quinn had apparently angered IRA remnants by standing up to them over the lucrative smuggling trade.

As a Belfast Telegraph headline aptly put it earlier in the week, Mr Quinn's killing is just one in a series of 'inconvenient murders'.

Frank Kerr, Andrew Kearney, Garda Jerry McCabe, Denis Donaldson and Robert McCartney: just some of the people who met violent deaths when the Provos were signing up to peace.

The wounds could re-open tomorrow, when an inquest is expected to hear details of the savage murder of former Provo spy Eamon Collins, who had written an immensely valuable book, Killing Rage, on the psychological motivation of the IRA's murder machine.

Sinn Fein's strong public response to Mr Quinn's murder has helped to limit political damage - so far - and, while not perfect, is a welcome advance on previous lukewarm condemnations.

However, the appearance this week of graffiti in Cullyhanna referring to the IRA as "murdering scum" should serve as a warning to republicans of society's complete rejection of criminality by the IRA and its remnants.