The body of the policeman murdered in the London terror attack will lie in a chapel in the Palace of Westminster before his funeral on Monday.
Pc Keith Palmer, 48, was stabbed to death by extremist Khalid Masood last month as he carried out his duties on the cobbled forecourt outside Parliament.
The Queen has given permission for the officer's coffin to rest in Westminster's Chapel of St Mary Undercroft.
It is an honour normally reserved for heads of state and which was bestowed on former prime minister Margaret Thatcher and Labour politician Tony Benn.
Pc Palmer's body will be brought to the chapel at 2pm on Sunday, with a special escort by the Metropolitan Police, where it will be greeted by a guard of honour.
A private service will be held, attended by close family members.
Reverend Prebendary Rose Hudson-Wilkin will stay with the coffin throughout the night, along with a catafalque guard of honour, before it is taken to Southwark Cathedral for a full police funeral.
Thousands of officers from across the country and members of the public are expected to line the route.
Four other innocent people were killed and dozens of others injured in the 82-second atrocity on Wednesday March 22, which ended with Masood being shot dead.
Andreea Cristea, 31, Leslie Rhodes, 75, Kurt Cochran, 54, and Aysha Frade, 44, died after he ploughed into pedestrians on Westminster Bridge.