Leaked documents of Operation London Bridge have revealed the Royal protocol if the Queen was to pass away at Sandringham.

The palace has made plans for each of the royal residences, though Sandringham was where two of the UK's last monarchs passed away, the Queen's father and grandfather, King George VI and King George V.

The day of the Queen's death will be referred to as 'D-Day', with the following days referred to as 'D+1', 'D+2', etc.

Immediately following the news of the Queen's death, the Prime Minister will be informed and all government buildings will lower flags to half-mast within 10 minutes.

HRH The Prince of Wales will address the nation at 6pm on the day of the Queen's death and the Prime Minister will issue a statement on behalf of the government.

The nation will have a minute of silence and a 'spontaneous' service for senior government ministers will take place at St Paul's Cathedral.

Prince Charles, who on 'D+1' will be proclaimed King by the Accession Council, will on 'D+3' go on a tour of the UK and its parliamentary buildings before the burial.

On 'D+2', Her Majesty would be taken by royal train from Sandringham to London, met at St Pancras by the Prime Minister and cabinet ministers.

The Queen's coffin will, on 'D+5', then be in a procession from Buckingham Palace to the Houses of Parliament, where she will lie in state for three to six days, open to the public for 23 hours a day.

Following this, the state funeral will take place at Westminster Abbey and Queen Elizabeth will be buried at Windsor Castle.

The day of the funeral will be considered a 'Day of National Mourning', effectively a bank holiday.

The leaked documents noted concerns of London reaching 'breaking point' this day, with hundreds of thousands of people flocking to the capital. Crowds are a major concern.

There will be another national silence for two minutes at midday and processions will take place in London and Windsor.