A fourth, senior officer - who should have been overseeing the operation - was forced to drive the van.
Portlaoise Prison is carrying out an internal investigation after a three officers were too drunk to escort a prisoner back from Dublin.
The incident, which occurred earlier this month, involved the escort a dangerous gangland criminal from the Criminal Courts of Justice.
A fourth, senior officer - who should have been overseeing the operation - was forced to drive the van, after the three junior officers spent part of the day drinking.
The van also stopped for a toilet break at the Junction 14 service station on the M7 - which is strictly prohibited while carrying a prisoner - and the three junior officers also attended the fast food outlet on site.
The incident came to the attention of management upon their return.
However, Special Correspondent with the Irish Examiner, Mick Clifford doesn't expect there will be major disciplinary action:
                            
            Median House Prices Rise In Midlands
        
            Literary Festival Kicks Off In Laois Tomorrow
        
            New Entrance To Laois Shopping Centre Gets Green Light 
        
            Midlands Winners For Family Carer Of The Year Announced 
        
            INTO Survey Reveals Job Vacancies In Over Half Of Special Schools 
        
            Offaly Mother Raises Almost €2k for Down Syndrome Ireland
        
            Laois TD Urges Stronger Support For Tillage Sector
        
            Midlands Agricultural Land Prices Surge 10% In A Year
        
            People Weren't Happy With The Choice - Spoil The Vote Campaign
        
            Cannonball Ireland Raises Over €2.2m For Children’s Charities
        
            Plans Submitted To Revive Fire Damaged Café In Laois
        
            Gardai Seek Help In Locating Hijacked Car In Midlands
        
            Ryanair CEO Pleased With Jump In Profits
        
            TDs Call To Deport Convicted Relatives In Ashling Murphy Case
        
            Former Mayor of Westmeath County Council Laid To Rest
        
            Cabinet to Consider Charges For Asylum Seekers In IPAS Centers
        
            Gardai Looking For Man Last Seen In Midlands
        
            Jobs Fair In Support Of Couriers To Take Place In Laois
        
            New ‘Give Take Return’ Recycling Pilot To Launch In Westmeath
        
            Muintir Na Tíre Honoured For 40 Years Of Community Service In Laois