The Prince also insisted on travelling in the high-visibility Rolls Royce Phantom rather than a lower-profile Jaguar, the Daily Mail claimed.
The Jaguar would have made the convoy more flexible as it had a better turning circle and could have used side roads, a source said.
The disclosure came as disturbing footage of the moment a mob descended on a car carrying the Prince of Wales and Duchess of Cornwall shows that a woman in her twenties was one of the main protagonists.
Police released CCTV images of the attack during last month's tuition fee protests in London.
They show that the woman, who has brown hair, hit the couple's Rolls-Royce three times before throwing a metal dustbin at a staff car, shattering its rear window.
Rolls royce phantom
Rolls royce phantom
Rolls royce phantom photo