Wellwishers intending to travel to Sandringham for the christening of Princess Charlotte this weekend have been urged to plan ahead by police.
With the service not due to start until 4.30pm, police say visitors will only be able to take up positions outside the St Mary Magdalene church from 3pm.
And officers are urging the public to plan their day, and to be prepared to queue for a long time in warm weather with limited refreshment areas, if they arrive early.
Supt Kevin Clarke, of Norfolk Police, said: “With this being such a special occasion we are expecting the area to be extremely busy on Sunday and encourage the public to heed our advice so they can enjoy the event safely.”
The Queen, the Duke of Edinburgh, the Prince of Wales and the Duchess of Cornwall will be among the guests attending the service, which is a private event.
The service will be led by the Archbishop of Canterbury, the Most Rev Justin Welby.
He will be supported by the Rev Canon Jonathan Riviere, the rector of the Sandringham group of parishes.
In a statement, Kensington Palace said: “The Duke and Duchess are hugely grateful for the warm wishes they have received since Princess Charlotte’s birth - many of them from local people in Norfolk - and are delighted the paddock can be opened on the day of the christening.”