Royal watchers at a church which was attended by the Queen on Christmas Eve were greeted by extra security.
Sandringham was built by the Prince and Princess of Wales in 1870
The service was held at St Mary Magdalene Church near the royal residence at Sandringham, Norfolk.
Police used electronic body searching devices to scan some visitors arriving in the grounds to see members of the Royal Family.
Visitors are not allowed to take cameras into the grounds of Sandringham House.
Police carried out checks on everyone arriving.
Members of the Royal Family, including the Duke of Edinburgh, The Duke of York, the Earl and Countess of Wessex, and the Duke of York's daughters, Princess Beatrice and Eugenie, joined the Queen for the 40-minute service.
About 100 members of the public gathered on the approaches to the church to watch the royals arrive.
The Queen travelled to the church by car.
Police said there were no specific reasons for carrying out electronic body checks of visitors.
They said the checks were part of standard security measures. But no regular visitors to Sandringham could remember such checks being carried out before.