The coffin bearing Prince Philip arrived at a fortified Windsor Castle Saturday morning in preparation for his afternoon funeral.

Heightened security measures include snipers set up on roofs, and hundreds of officers wearing purple vests stationed throughout the town, in what local reports are referring to as a “Ring of Steel” in place for the Duke of Edinburgh’s sendoff.

Police are prepared to start closing roads if crowds start to gather, despite warnings urging the public to stay away.

Armed cops wearing body armor — not a typical sight in Britain — patrolled the historic town and police boats moved up and down the Thames River, The Sun reported. Police even sent divers into drains close to the castle, where Prince Philip will be interred in St. George’s Chapel.

The coffin was moved at 11 a.m. by a party from the Queen’s Company, 1st Battalion Grenadier Guards to the royal residence, according to The Sun. Prince Philip served as colonel of the Grenadier Guards for 42 years.