Why doesn’t discipline extend to drug abuse?

I AM surprised that a serving prison officer puts his head above the parapet on the issue of clean needles in prisons (Irish Examiner letters, September 22).

A prison is designed to keep criminals from society. This is done by locks, bars, high levels of supervision and controlled contact with the outside world. There is little cash available to the inmates.

These are circumstances which the average drug dealer would run a mile from and yet there is more drug abuse in our prisons than in most of our blighted city centres. This is incomprehensible to most people given the high levels of security and supervision.