MONITORING for increased levels of bed bugs and fleas; equipment for detecting human odours; burying microphones underground and employing chemical and biological sensors…
Just a few of the dozens of ideas considered by the prison authorities, in the mid-70s, to counteract prisoners digging tunnels to escape the Maze.
Northern Ireland office files from 1974 and 1978, reveal the battle to beat the paramilitary digger
s involved the excavation of every conceivable option.
Following 12 tunnel attempts in 1973-74, a report was commissioned on ways to combat the tunnel rats.
It now emerges that prison authorities privately admitted it was impossible to stop tunnelling, among inmates given special category status.
“While upwards of 80 prisoners per compound have virtually unrestricted movement within each compound and are also permitted unsupervised handicraft activities, escape attempts can be expected,” a report noted.
The emphasis was therefore to be on detection, rather than prevention.
The soft, sandy soil at the Maze was rated good for tunnelling and it generally did not need shoring because the compound tarmac and the old runway surfaces acted as a natural ceiling.
And the report on how to detect tunnels, added to the problems, as it said: “As far as we know, there is no low cost, fool-proof device which can be guaranteed to detect tunnelling.”
The key was to detect “before significant progress is made ie: before a tunnel reaches a compound fence.”
The search for detection devices, however, was proving as difficult as the search for the tunnels.
In 1974, it emerges, an “anti-tunnel barrier” was proposed as the solution.
And work took place, involving trench sheet piling.
Each pile was 13 feet long and a foot in width. The piles would be inter-linked and a compressor driven hammer employed to force them into the ground.
A two feet deep trench- running 375 feet – was dug inside the compound, so that once the piles would be driven in, there would be a 15 feet barrier.
It took 23 days to complete the work, but an attempt to then alarm the barrier failed and the Army was eventually called in to remove the barrier.
The search solutions went on and several dozen ideas were explored.
Many related to acoustic methods of detection.
Microphone systems, similar to those employed in prisoner of war compounds in World War II. Buried microphones, acoustic Grave Detectors, microphone cables.
Then there were seismic sensors, magnet sensors, chemical and biological sensors, vibration sensors, pulse radar, thermal imaging, ultrasonic imaging and x-ray and nuclear methods and infra-red photographic technology.
