Butt, a 27-year-old Pakistan-born British citizen, and his two accomplices, Rachid Redouane, 30, who claimed to be Moroccan-Libyan, and Youssef Zaghba, a 22-year-old Italian national of Moroccan descent, were shot dead by armed police eight minutes after the first emergency call.
In this image taken from video which emerged on social media shows police surround an attacker on ground at right, during the terror attack in Borough Market in southeast London Saturday June 3, 2017.
Then, eight weeks later, three Islamists staged a carbon-copy attack on London Bridge.
Speaking after police revealed the ringleader of the London Bridge terror gang tried to hire a 7.5 tonne lorry hours before the attack, she urged people to report anything they deem suspicious.
The spate of recent attacks - the deadliest in Britain since four British Islamist suicide bombers killed 52 people on the London transport system in July 2005 - thrust security and policing to the fore of the campaign for last Thursday's election.
It's been a awful week since the London Bridge attack, but Dick takes some pleasure in the way the city's buzzy street life has returned full force.
The three terrorists had tied 12 inch (30cm) pink ceramic knives to their wrists and had petrol bombs in the van, it said.
Multiple petrol bombs were discovered in the van used in the outrage, while a copy of the Koran opened at a page "describing martyrdom" was discovered in the east London bolthole where the three men plotted the attack.
Commander Dean Haydon, head of the Met's Counter Terrorism Command, said, "We've been working round the clock to understand what these men did in the lead-up to the attack but we need to know more about these unusual knives".More news: Apple New, Faster iMacs & MacBooks Plus macOS High Sierra
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Police raided Redouane's small residence on Tuesday and said he had been renting it since April.
In addition, Thirteen Molotov bottles with an incendiary mixture, two blow lamps, and office chairs, which investigators think were used as a cover to rent the vehicle, were found in the terrorists' minivan.
He is the 19th person arrested in connection with the attack, but twelve of the individuals were released this week without charge.
The three attackers were wearing hoax suicide belts consisting of plastic water bottles wrapped in grey duct tape.
The police and intelligence agencies have tried to prevent complex, high-tech plots - such as those created to bring down commercial flights - but now they are dealing with a rash of less complicated attacks on soft targets, she said. Luggage straps, plastic retractable craft knives and rolls of duct tape were also found. All but five have been released.
The trio were shot dead by the police.
"It looks as if it is pretty much a contained plot involving the three of them, which is supported by the forensic evidence we've got back so far", Haydon said.
Speaking in quiet, measured tones, the 56-year-old points out that London has been hit by terrorist attacks throughout her life.
When asked if the Metropolitan Police needed more resources she said: "We will want more resources to help us and I am sure the same will be being said in the intelligence agencies".