Commissioner Dame Cressida Dick said the force has been planning for July 4 “for some time” and the public will see “a lot” of officers on the capital's streets.
The commissioner warned pub-goers venturing out on Saturday to remain calm and "be sensible".
“We’re planning, we’ve got extra resources in place, we’re talking to people in every way we can think of, we are absolutely prepared," she told the BBC.
“You will see a lot of police officers out on the street.
"There will be a lot more ready should people be out of order, should people get violent. But I’m not predicting that at this stage.”
London has seen tensions flare during recent protests and a number of unlicensed music events.
Dame Cressida added: “We have seen over recent weeks feelings have been running high in a number of areas for lots of different reasons.
“Coming out of lockdown, the events after the death of George Floyd. Lots of people are quite cross about a lot of things, and we are seeing people out on the streets and not always observing social distancing.
“My message is, if you’re coming out on Saturday, be calm, be sensible. Look after yourself, look after your family.
“We are still in a global pandemic which is affecting this country very obviously. People need to be sensible.”