The petrol bomb, believed to be the work of loyalists, set the living- room of the house alight as the four - a Protestant woman, her two children and her Catholic boyfriend - were in bed upstairs.
In two other attacks, which police believe were carried out by the same gang, a device was thrown at a Catholic home but failed to ignite, while a Catholic primary school was extensively damaged and had to be closed.
These and a series of other attacks are linked to a bitter and long-running dispute in which loyalists have been picketing Catholics attending Mass at a church in the mainly Protestant town of Ballymena. The loyalists are protesting because Protestant marchers have been prohibited from parading through the nearby Catholic town of Dunloy.
Such disputes are normally associated with the loyalist marching season, which came to an end in August, but the picketing has now gone on for 11 weekends. Unpleasant scenes have resulted, and last week the protest degenerated into violence, with loyalists burning a bus and throwing a petrol-bomb at police. Fears are growing that further violence may follow this weekend.
Since the crisis which followed July's Drumcree Orange march stand-off, there has been sporadic sectarian violence in Northern Ireland, with the majority of such attacks being directed against Catholics.
Another casualty of the Drumcree crisis has been Catholic confidence in the North's police force, the RUC. Before Drumcree, there was a growing acceptance of the RUC in the Catholic community. But a new survey by the Northern Ireland Police Authority revealed yesterday that a large majority of Catholics now have little faith in the RUC: Two thirds of Catholics now believe that the police treat Protestants better than Catholics. The survey also revealed that a majority of the Northern Irish population wanted to see the RUC either reformed or disbanded.
Since the marching season ended, there have been scores of attacks such as the one in Ballymena yesterday, mostly by Protestants against Catholics and their property. But there have also been numerous instances of attacks on Protestant targets.
Early yesterday, for example, a fire was started maliciously inside a Protestant church near Cookstown, Co Tyrone, damaging the pulpit. Catholic churches have been a favourite target, especially in the County Antrim area, but schools have also suffered.
Two weeks ago the Government said there had been arson and other malicious attacks to more than 20 schools, causing damage estimated at more than pounds 3m. A number of schools have been attacked repeatedly.
Yesterday the Catholic boyfriend of the Protestant woman whose house was burnt said: "Suddenly the window broke and a petrol-bomb came through the window and the house went on fire. I went in, lifted the two children out of their beds and rushed them down the stairs and out through the front door."
An RUC chief inspector, Roger McCallum, said: "I believe this was probably the latest manifestation of naked sectarian violence which we have seen in Ballymena in the past week."
t More arms have been discovered close to the Irish Republic's border with Ulster where a series of weapon finds were recorded last month. Irish police and Army personnel uncovered a mortar tube, mortar plates and bomb- making equipment near Hackballscross, Co Louth which the IRA are thought to have stored over a number of years.