One of Buckingham Palace's most time-honoured traditions - Changing the Guard - is switching to fixed days in the autumn and winter.
It comes after security was stepped up in the wake of the Berlin terror attack.
The colourful military spectacle, which usually takes place on alternate days between August and March, will now be held on Mondays, Wednesdays, Fridays and Sundays during this period.
The time of the event has also been changed, with the ceremony at the Palace taking place at 11am, rather than 11.30am.
The ceremony at Windsor Castle will also see changes. It will coincide with the Changing of the Guard at Buckingham Palace, aside from Sundays.
During the summer, the Changing of the Guard will still take place every day.
The changes are at the request of police and transport officials in London.
The event is known for its popularity amongst tourists, with thousands flocking to Buckingham Palace, the Queen's official residence, to see the soldiers in their iconic red tunics and bearskins take part in the spectacle.
The display is an impressive one- the famous bearskin hats worn by the Guard can be up to 45cm tall and weigh around 0.7kg.
The change in schedule is part of increased security measure designed to prevent a Berlin-style lorry attack, following an incident which took place in December in which a truck packed with steel ploughed into a Christmas market, killing 12 people.
In order to prevent such an attack, roads around the Palace are closing to traffic whilst the ceremony is taking place, and additional barriers have been put in place to maintain security for the guard movements.
The Metropolitan Police said in a statement:
"The Met undertakes a range of different activities including strengthening security and high-visibility policing as part of a counter-terrorist strategy, and it will continue to take whatever action it believes is necessary to protect and reassure the public."
At the moment, with the threat level for international terrorism listed as "severe", an attack is highly likely.
The changes will begin on January 16, with the hope that the change in schedule will reduce the disruption caused by road closures.
A spokesman for The Royal Parks said:
"This new programme allows the public, visitors, motorists and businesses to forward plan following new road closures on Guard Change days which were introduced in December as part of ongoing security measures aimed at keeping the public safe."
During the traditional ceremony, also known as Guard Mounting, the soldiers on duty line-up to be replaced by the New Guard, which arrives from Wellington Barracks, accompanied by a Corps of Drums.
The ceremony represents the formal handing over of responsibility, and is usually carried out by one of the five Foot Guards Regiments of the Household Division. It has taken place since 1660.