The Duke of York has criticised Ministry of Defence chiefs for failing to "get off their fat backsides" over ordering armoured vehicles.
He was speaking about the MoD wanting independent tests carried out on the new Ranger vehicles.
"I would say to you that regrettably they will not get off their fat backsides," the Duke said on a tour of the Ranger factory in Weymouth, Dorset.
An MoD spokesman said the Ranger did not meet current requirements.
Prince Andrew was visiting Universal Engineering as part of his role as a UK trade ambassador.
He was shown the new Ranger vehicle, which the company claims offers superior protection for troops from the threat of roadside bombs.
The Dorset Echo reports that he was told the company had already carried out tests to show what protection the vehicles could offer, but the MoD had asked for independents tests before considering any orders.
"Why do they have to do blast tests?" he is reported as saying. "It's just increasing the cost.
"It just seems that because it takes time to get these things done - I would say to you that regrettably they will not get off their fat backsides."
He went on to observe that the MoD is "completely hopeless at these kind of things".
Roadside bombs, or IEDs, have been a regular threat to soldiers in Iraq and Afghanistan.
The MoD has said previously it had no immediate plans to order the vehicles, but had asked for tests to determine the Ranger's resistance to roadside bombs.
An MoD spokesman said: "We have looked into the Ranger vehicle but it does not meet any of our current requirements.
"The size and weight of the prototype Ranger vehicle is similar to that of our Mastiff and Ridgeback vehicles that are already being used in Afghanistan.
"In the event that future operational requirements are identified for a vehicle of its type then the Ranger could be considered."
Buckingham Palace refused to comment on the Duke's comments, saying it was a "private conversation".
It is royal protocol that members of the Royal Family do not express political views in public.