Steel barriers, concrete blocks and weapons checks will help protect Notting Hill Carnival from the threat of a Barcelona-style terror incident and acid attacks, Scotland Yard said.
David Musker, the commander in charge of policing the west London event, said there was no specific counter-terrorism intelligence but security plans had been "thoroughly reviewed" after the Barcelona attack, in which 15 people died after being hit by a van.
Officers will be stationed around the perimeter of the carnival zone, carrying out checks for weapons and corrosive substances, following a controversial three-week crackdown to reduce criminality at the event.
But the Yard faced criticism from campaign groups over its planned use of facial recognition technology, which will help the force spot those thought to be likely to cause trouble.
Chief superintendent Robyn Williams, responsible for community engagement, said the carnival would look different to people, with large concrete slabs erected from 6am on Sunday "to keep vehicles and any other large obstacle from actually entering into the footprint" of the carnival.
Vehicles such as floats will not be able to enter or leave the area before 9am and after 7pm.
Officers will also have nitrile gloves, extra water supplies and testing facilities for corrosive substances following an alarming spate of acid attacks in the capital over the past few months.
Mr Musker said: "People should be under no illusion that if they think they can swan in with a bottle of Lucozade with acid in and not be able to be detected by police, we have the methods, the people, the highly-trained professionals, and we will look at them, and I will press for them to be arrested and charged and brought before the courts."
While extra officers will be stationed around Grenfell Tower in a "ring of care", to protect the Lancaster West estate from carnival-goers, overall policing numbers will stay the same as last year, with approximately 15,000 shifts worked over the two days.
This works out as around six to seven thousand officers on duty each day.
A three-week crackdown on crime ahead of the carnival saw 656 people arrested by 7am on Friday, and a large number of knives, guns, weapons and money seized, the Met said.
The force hit back after being criticised for linking a series of dawn raids earlier this week to the carnival, with Mr Musker saying: "I think the public would expect us to do what we can to prevent those injuries to people coming to carnival."
Facial recognition technology will be used as part of a trial, and "super recognisers" will also be in place in an attempt to weed out potential troublemakers from the throng.
Mr Musker said he was "not blind to the fact that this is a controversial tactic", adding the Met had consulted with the Biometrics Commissioner, Information Commissioner, and campaign group Big Brother Watch "to ensure that what we are doing is proportionate, legal and effective".
He added: "It's not loaded, it's loaded with people who we know are involved with criminality, who are wanted.
"It's not a speculative search tool."
Big Brother Watch said it had met with the Met once in 2016 and denied providing assurances of the technology, with the Open Rights Group urging the force to abandon the technology given it "can have racial biases, which risk discriminatory policing".
Liberty campaign group has been invited to observe the force's tactics, Mr Musker said, adding: "If we're going to use this we've got to get this right".
It comes as the National Police Chiefs Council warned the public to stay safe over the bank holiday weekend, with a number of sporting events and festivals planned.