A Catholic theologian has said the dregs of society ran institutions where children were abused by what he called monsters.

However, Fr Vincent Twomey also praised many other members of religious orders for caring for vulnerable people who had been abandoned for centuries by British administrations here.

He was speaking on BBC Radio Ulster's Sunday Sequence programme.

Father Twomey is a former doctoral student of Pope Benedict and meets him annually.

Acknowledging that priests, brothers and nuns in authority had known about ‘the reign of terror’ in their institutions, he asked how it was possible for religious who were ‘devoted to Christ and the care of children to turn out to be monsters’.

He said many of them came from large and extremely poor families and their parents had pressurised them to enter congregations because of the social status and life-long security they offered.

Fr Twomey said many did not have real vocations, and were frustrated sexually because celibacy was not their choice.

He said what we were looking at were ‘the dregs of society in a certain sense’ and that they ‘ran the schools’ the Child Abuse Commission had condemned in the Ryan Report.