More than 4,000 police officers will be on duty tomorrow for Baroness Thatcher's funeral, Scotland Yard said today.
The force also revealed that "a small number" of protesters have contacted police to say that they plan action during the event.
It is expected that the main focus of the policing operation will be public order issues, and some protesters have already declared their intention to turn their backs on the funeral procession as Lady Thatcher's coffin passes on a gun carriage.
The Metropolitan Police is running a joint operation with City of London Police and British Transport Police for tomorrow's ceremonial event.
Commander Christine Jones said: "We have been approached by a small number of people planning to protest. We are working with them, and would ask anyone who plans to protest to come forward and speak with us today.
"We will continue to review our intelligence and evidence picture, and although to date no arrests connected to the Ceremonial Funeral have yet been made, should the need arise to arrest those who are committing acts of crime or violence, or conspiring to do so, we will respond accordingly."
The force will have to balance public order concerns with guarding visiting dignitaries and the possibility of more extreme threats such as attacks by dissident Republican groups from Northern Ireland.
Cmdr Jones went on: "Every operation that we deliver is based upon a thorough assessment of the potential risks and threats, and we plan the most effective ways to mitigate against them.
"We wish to deliver our operation in a way that protects public safety within the context of a broader security operation - as with many ceremonial London events.
"The right to conduct peaceful protest is a tenant of our democracy, however that right is qualified in that protest does not stray into acts of crime or violence or the instigation of crime or violence.
"The policing operation for the funeral of Baroness Thatcher will see officers deployed in a range of functions appropriate to meet the demands of the overall policing operation.
"We will be deploying a number of officers at points along the route, and there will be road closures in place. If you are planning on travelling into London, please plan your journey and allow plenty of time."