I said... I am STUNNED that they had a opt out. I know several catholic solders who served and said that they had to go. And one guy who was injured in training and didn't go and with hindsight and age said he was glad.
I think there was also an element that if they had connections to the community they might not be entirely trustworthy as they would have difficulty detaching loyalty to the community and loyalty to the Queen. On the other hand, they can also be useful as they provide intelligence that couldn't be garnered otherwise. I believe that is the case with Muslim recruits today.
http://www.channel4.com/programmes/sunday/4od#3053373
The story is told from the point of view of Leo Young, who was out on the Bogside march with his sister Maura and his younger brother John. Leo's mother had asked him to look after his little brother. The film tells the Young family's story - how John was killed by a British Army soldier, and the pain and grief they felt as a result.
This drama-documentary also examines the political context for Bloody Sunday, and the impact of the first official Government Inquiry into the day itself, which was conducted by the then Lord Chief Justice, Lord Widgery, in 1972.
It was made with the full consultation and co-operation of the families affected by the tragedy, and was carefully researched over several years by an experienced factual production team. More than a hundred first-hand interviews were conducted with British soldiers and officers, priests, politicians, medical experts and eyewitnesses, as well as with relatives.