A VEHICLE which sliced off its roof when it hit a low bridge in Banbridge was a prison van.
The collision happened on Sunday as the van drove under The Cut, a 19th century stone bridge in the Co Down town.
The driver did not notice the damage and drove on for 10 miles towards Portadown.
A spokesman for the prison service said one of its vehicles "was involved in a road traffic incident at Banbridge on November 27".
The crash is being investigated.
A second vehicle - a lorry - hit the bridge on Monday night.