London — Concern is growing that the illegal Irish Republican Army is trying to trigger all-out civil war in Northern Ireland. A series of IRA acts in recent days prompted bloody retaliation from Protestant hardliners over the weekend.
Leading Roman Catholic politician Gerry Fitt said that the IRA is seeking full-scale civil war by trying to provoke Protestants to retaliate against Catholics.
And there is a definite feeling both in Whitehall and in Belfast that the crescendo of violence is apparently developing - as British Northern Ireland Secretary James Prior suggests - because the IRA is getting desperate in its attempts to put pressure on the British government.
Just over a month ago, the IRA prison hunger strike crumbled in face of Prime Minister Margaret Thatcher's unbending toughness. IRA leaders are also worried by the good relationship established by talks in London between Mrs. Thatcher and Irish Prime Minister Garret FitzGerald.
Cross border security between the republic and Ulster was high on the two leader's agenda. It is believed here that the IRA wants to make the point that nothing will blunt its resolve to embarrass the British authorities in Belfast.
The last few days have seen:
* The murder of the Rev. Robert J. Bradford, a Unionist member of the British Parliament killed by IRA gunmen Nov. 14. Also killed in the attack was the caretaker of the community center where Bradford was addressing constituents.
* One Catholic teen-ager was shot and killed and another seriously injured Nov. 15 - apparently in a Protestant retaliatory attack.
* Earlier the home of Britain's attorney general, Sir Michael Havers, was bombed by the IRA Nov. 13. It was not occupied at the time of the bombing and no one was seriously injured. This followed several bombings in London last month.
* Two policemen were shot and wounded Nov. 14 while on patrol in a Catholic district of Belfast.
The killing of the Rev. Mr. Bradford, a parliamentary ally of the Reverend Ian Paisley, has been taken as a signal that the lives of all MPs with an interest in Northern Ireland affairs are at risk. (Shortly before she became prime minister, Mrs. Thatcher's chief adviser on Northern Ireland affairs, Airey Neave, was murdered when his car exploded on leaving the House of Commons parking lot.) Security measures to protect prominent British politicians have been sharply intensified.
Another response thought to be under consideration by Prior is greater use of the British Army's crack Special Air Services unit. The SAS is highly trained in counterinsurgency techniques. Its members are able to infiltrate terrorist groups and are well able to hold their own in encounters with Ulster's armed groups.
Prior is unlikely to call in the SAS in a major way without long and careful consideration. But he is under growing pressure from Protestant groups in Northern Ireland to improve antiterrorist measures.