General election 2017: Politicians’ promises for keeping us safe
In a specialist care home in south London Patrick Boyce leans over his teenage son's bed and wipes his mouth.
"He can't move, he can't feed himself, he's blind, there's no speech," he explains.
Jamel, 17, was stabbed in the heart outside a supermarket seven months ago. Paramedics brought him back from the dead, but his quality of life is now extremely low.
He had never been in trouble with police and never carried a knife.
He is another victim of London's knife crime, something his dad describes as an "epidemic".
"It's just like demons have taken over the youth of today. There are no morals, there's no love. It's insane," he said.
The new Commissioner of the Metropolitan Police Service, Cressida Dick, was among those who said they were moved by Patrick's words.
So how are London's politicians promising to help Scotland Yard tackle knife crime, and more broadly, help to keep us safe?
Note: All the parties wrote their manifestos before the Manchester suicide bomb and the London Bridge attack but they had all promised to step up the fight up against terrorism, in different ways.
Labour say they will pay for 10,000 extra police officers across the country.
The party claim they are vital for community safety as well gathering intelligence in the fight against terrorism.
But shadow home secretary Dianne Abbott, who initially struggled to explain how much they would cost, also couldn't say how many additional PCs London would get.
The Conservatives are not promising extra police, but Minister for London Gavin Barwell has said the Tories will protect the police budget and recruit more officers into the security service MI5, MI6 and the UK's communications intelligence agency, GCHQ.
The Tories also say they'll improve the response to cybercrime by incorporating the Serious Fraud Office into the National Crime Agency.
The Liberal Democrats say they'll invest an extra £300m in local policing.
The party claim this will reverse a recent increase in violent crime - last month the Met said knife crime had risen 24% and gun crime has gone up 42% over the past year.
Sir Vince Cable, the party's shadow chancellor, said he was concerned Brexit would affect the sharing of intelligence which could prevent a terrorist attack.
The Lib Dems - along with the Greens - are offering a second referendum on Britain's membership of the EU.
UKIP say they'll recruit an extra 20,000 police officers. Again, it's not clear how many would be in London.
Deputy leader of UKIP Peter Whittle, a London Assembly member who stood as the party's mayoral candidate last year, said his party had calculated the move would cost £1.3bn.
UKIP has also promised to hire 7,000 more prison officers and bring 4,000 more staff into the border force to better prevent terror suspects coming in and out of the UK.
The Green Party say they, too, will invest more in community policing.
They believe eyes and ears on the ground is a vital way of gathering information which can be used to help thwart terror plots.
Sian Berry, another London Assembly member who ran in the 2016 London mayoral election, says the government's Prevent strategy for tackling extremism needs to be re-worked.
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So, for many parties the promise of more bobbies on the beat is a popular one. Polls show people like the sight of an officer pounding a street near them particularly at a time of high alert.
Three UK terror attacks have succeeded this year and Scotland Yard says it has foiled five other plots since the Westminster Bridge attack in March.
In all, 18 attacks have been stopped since 2013 but aside from the huge challenge of combating terrorism, the nature of other crime is changing.
More investigators are needed to deal with specialist crime, including fraud and sexual offences.
Last week the Met said it would start recruiting members of the public as detectives as it tries to fill 600 vacancies at Scotland Yard.
But when it comes to policing, there is only so much politicians can do.
The mayor of London, for example, helps set the Met's budget and gives priorities, but it is Cressida Dick who has full operational control.
For example, she has already said she would back an increase in the use of stop and search if it were intelligence-led and brought down knife crime.
For Patrick Boyce though, still at his son Jamel's side, any victory in the war against knives in the capital will be hollow.
He says victims' families have been failed by successive politicians of all colours who haven't been tough enough.
Patrick believes young people need to be given more discipline and structure, whether it's a job, training or even military service.
"If these guys want to go round killing people, carrying knives, then put them in the army," he said.
Jamel Boyce turns 18 in August and it should have been the happiest of celebrations.
But rather than planning a party, Patrick is arranging the complex care his boy will need for the rest of his life.
"It's not just my son I've lost. I've lost my friend, my confidant, my future really."