The RPG rocket attack on the MI6 headquarters at Vauxhall Cross on the Thames on Wednesday night was what Provisional IRA supporters used to call a "spectacular". The IRA "spectaculars" of the early 1990s in England involved attacks that were of no military effect but which provided a large media spectacle.
One of the most significant was the mortar attack on 10 Downing Street during the Gulf War. The achievement was not in the human or material damage caused but in the embarrassment of striking a blow at the heart of Westminster at such a crucial time. One of the mortars landed in the back garden of Number 10, showering the then prime minister, Mr John Major, and his Cabinet with glass from shattered windows.
The attack on the MI6 building is a success for the "Real IRA" in that it has attracted a high volume of media attention, with the added bonus of embarrassing the British intelligence services.
The so-called "Real IRA" bombers now operating in England have therefore achieved their first big military/propaganda coup against the British government. This, despite the fact the RPG rocket would have broken only a window or two in the monolithic steel and concrete building on the Thames and that the more likely target would have been on the other side of the river, the location of MI5 - the domestic intelligence agency which deals with "Irish" terrorism.
The attack was a further success in that there were no civilian casualties - an important factor for a group that will be forever notorious for the Omagh bombing.
The timing of the MI6 attack, on the eve of the crucial South Antrim by-election test of unionist support for the Belfast Agreement, shows dissident republicans are now capable of combining military capability with propaganda effect.
The group had unsuccessfully tried this several times. On St Patrick's Day 1998 it attempted a bombing operation in the North in an effort to embarrass Sinn Fein leader Mr Gerry Adams, who was meeting President Clinton in the White House. That bomb was intercepted by the Garda.
In Easter 1998, in the days approaching the signing of the Belfast accord, another "Real IRA" bomb was stopped by gardai as it was about to be driven on to the Holyhead ferry at Dun Laoghaire, destined for the Grand National at Aintree.
An attempt to establish a bombing unit in London in 1998 to cause damage and disruption to undermine the new agreement was also thwarted by gardai. Three young Irishmen, students recruited to the new organisation by figures in the Republic opposed to the agreement, were arrested in London as a result of Garda intelligence work.
It is expected they will be transferred to prison in the Republic. This time the anti-Belfast Agreement republicans appear to have learned from their previous mistakes and have eluded the Garda and British security services.
The unit in London, which gardai suspect is again made up of young people with no previous history of involvement in republican terrorism, has already carried out two disruptive bomb attacks. These small-scale bombings - at Hammersmith Bridge on June 1st and a month later at Ealing Broadway - may have been used to test the unit's security and capabilities. The attack at Vauxhall Cross, and some of the recent attacks in Northern Ireland, show an organisation growing in confidence.
IT appears to have its main support base in the Republic. Former Provisional IRA bomb-makers from Dublin and the Dundalk area have contributed to its technical skills. Since February there has been a growing geographical spread of attacks in the North - from Fermanagh, to south Armagh, to Derry and to Belfast.
The group does not admit attacks, maintaining the fictional ceasefire it announced - apparently in fear of its members being interned without trial - after the Omagh bombing. It occasionally allows admissions in the name of the other dissident republican group, the Continuity IRA, a group that has some support in the northwest.
The Continuity IRA is small, but growing. It was behind the abduction and ransom of a bank official and his wife in Strabane, Co Tyrone, two weeks ago.
Senior security figures now express concern that the dissidents, particularly the "Real IRA", are reestablishing themselves after Omagh. They have sufficient income to buy reasonably large shipments of high-quality arms from dealers in Croatia and have established a secure recruitment network.
It is expected they will pursue their principal aim of damaging the Belfast Agreement, and particularly the Sinn Fein leadership of Gerry Adams which supports it, with renewed vigour.
This will serve to add weight to the parallel opposition within unionism and loyalism against the Belfast Agreement. Security figures anticipate more difficult times for the peace process in Northern Ireland.