A Prison Service source suggested the prison van ambush would probably involve one of the escapees having access to a smuggled mobile phone.
A phone call could then be made or a text sent to let the armed gang know which prison van they were in and so which vehicle to target, among the number of vans making their way from jail to Manchester Crown Court.
More top news
The man, who was in his 30s, has not been identified, while several other people are believed to have suffered serious injuries.
The Olympian was one of several sports stars who opened up to the prince during an event for his mental health charity Heads Together.
There will be sunny spells, with temperatures peaking at 23 Celsius (73F). However, Northern Ireland will experience frequent showers.