The Department of Home Affairs says giving out information about prison staffing and procedures would undermine security at the Jurby facility.
A Freedom of Information request asked for details and policies about safe staffing levels and contingency plans for being short-staffed.
But in its response, the department said revealing the data could undermine the safety of inmates, officers and visitors.
And it added if it was made public, it could be used to identify operational vulnerabilities.
Cavendish reveals what he loves most about life after cycling
Manx Missile Mark Cavendish has told an Australian magazine he's 'living the dream' since his retirement from cycling.
Spar warns smokers and vapers of price rise
Spar Isle of Man says you should brace yourself if you smoke or vape this week.
Ramsey, Castletown and Laxey promenades to close overnight
The Department of Infrastructure says more promenades around the Island will be shut from the early hours of tomorrow morning.
David Ashford elected as new Speaker
David Ashford has been elected as the new Speaker of the House of Keys this afternoon.
Reservoir levels still low, data shows
The latest data from Manx Utilities shows the Island's reservoirs are still below their normal levels after a prolonged dry spell.
Weather means early hours closure for road in Onchan
A road at the northern end of Douglas Promenade will shut in the early hours of tomorrow morning.
Second weather warning issued by Met Office
Ronaldsway Met Office has issued a second warning about bad weather today.
Island fireworks team named brightest sparks
An Island fireworks company has won a prestigious award in the UK.
