King Charles was in favour of a larger procession through London for his coronation but senior aides were concerned about the extra policing costs.
With little more than three weeks to go before the big day, there remains plenty of organising still to be done before the crowning at Westminster Abbey.
One of the incognitos had been over the attendance of the Sussexes and that has now been cleared up with Harry, but not Meghan and the children, being at the coronation.
More details are emerging about the ceremonial celebrations including the procession route, the carriages and the priceless Crown Jewels chosen to play a starring role.
Charles and the Queen Consort will travel in a shorter procession route than the late Elizabeth II.
The King did want a larger procession that would take him and the Queen through the streets of central London but there were worries about how much it would cost, said royal insiders.
Senior aides decided it would be too elaborate and the costs too high for policing during a cost of living crisis.
King Charles’s coronation service was originally planned to last 90 minutes - considerably shorter than the late Queen's coronation in 1956, which lasted for three hours and 20 minutes.
Plans seen by The Mirror now show the service beginning at 11am and finishing at 12.45pm, with the King’s procession setting off from the Abbey back to Buckingham Palace at 1pm.
Our source added: “Everything should be planned to the minute and such overruns would be a disaster.
“The schedule from the programme, the carriages, balcony appearance and the RAF flypast is planned to the minute, so it’s all incredibly stressful.
“If the service is too long, or too complicated, the television audience will turn off and that could be devastating.
“(We) want to create a sense of majesty and Charles and Camilla have seen months of protests by a growing republican movement."
There will be a break with tradition as the King and Queen will only use the 260-year-old Gold State Coach one way - on the return.
The monarch and Camilla have personally decided to make the 1.3 mile outward journey - known as the King's Procession - from Buckingham Palace in the more modern, comfortable Diamond Jubilee State Coach, which has shock absorbers, heating and air conditioning.
They will travel, accompanied by The Sovereign's Escort of the Household Cavalry, down The Mall via Admiralty Arch, along the south side of Trafalgar Square, along Whitehall and Parliament Street, around the east and south sides of Parliament Square to Broad Sanctuary to arrive at the Abbey.
